Micro cellulose fiber complex

ABSTRACT

A fine cellulose fiber composite containing fine cellulose fibers and a polymer having an ethylene oxide/propylene oxide (EO/PO) copolymer moiety or a propylene oxide (PO) polymer moiety, the fine cellulose fibers being connected with the polymer via an amide bond. The fine cellulose fiber composite of the present invention has high dispersibility in the resin and can exhibit an effect of increasing strength, so that the fine cellulose fiber composite is suitably used as various fillers, and the like. Also, the resin composition of the present invention containing a dispersion of the fine cellulose fiber composite can be suitably used in various industrial applications such as daily sundries, household electric appliance parts, wrapping materials for household electric appliance parts, and automobile parts.

FIELD OF THE INVENTION

The present invention relates to a fine cellulose fiber composite. Morespecifically, the present invention relates to a fine cellulose fibercomposite which can be suitably blended as a nanofiller in dailysundries, household electric appliance parts, automobile parts, and thelike, and a fine cellulose fiber composite dispersion and a resincomposition each containing the fine cellulose fiber composite.

BACKGROUND OF THE INVENTION

Conventionally, plastic materials derived from limited resourcepetroleum have been widely used; however, in the recent years,techniques with less burdens on the environment have been spotlighted.In view of the technical background, materials using cellulose fibers,which are biomass existing in nature in large amounts have beenremarked.

Patent Publication 1 discloses a polyester resin composition containinga polyester resin and a fine cellulose fiber composite in which finecellulose fibers are bound with a hydrocarbon group via an amide bond,wherein the fine cellulose fiber composite has an average fiber size offrom 0.1 to 200 nm.

Patent Publication 1: Japanese Patent Laid-Open No. 2013-151636

SUMMARY OF THE INVENTION

The present invention relates to the following [1] to [3]:

[1] A fine cellulose fiber composite containing fine cellulose fibersand a polymer having an ethylene oxide/propylene oxide (EO/PO) copolymermoiety or a propylene oxide (PO) polymer moiety, the fine cellulosefibers being connected with the polymer via an amide bond.[2] A fine cellulose fiber composite dispersion, containing a finecellulose fiber composite as defined in the above [1] and a plasticizer.[3] A resin composition containing a thermoplastic resin or a curableresin and a fine cellulose fiber composite as defined in the above [1].

DETAILED DESCRIPTION OF THE INVENTION

In the composition containing a fine cellulose fiber composite of PatentPublication 1, it is not yet said to be sufficient in satisfying bothtransparency and mechanical strength.

The present invention relates to a fine cellulose fiber compositecapable of providing a resin composition having a smaller amount ofaggregates and having excellent transparency and heat resistance whenblended with a plasticizer, and having excellent transparency andmechanical strength when blended with a thermoplastic resin or a curableresin, and a fine cellulose fiber composite dispersion and a resincomposition each containing the composite. In addition, the presentinvention relates to a fine cellulose fiber composite capable ofproviding a resin composition having excellent mechanical strength whenblended with a thermoplastic resin or a curable resin that does notrequire transparency, and a fine cellulose fiber composite dispersionand a resin composition each containing the composite.

The fine cellulose fiber composite of the present invention can providea resin composition having excellent transparency and mechanicalstrength when blended with a thermoplastic resin or a curable resin(hereinafter simply referred to as a resin), and a resin compositionhaving excellent mechanical strength when blended with a thermoplasticresin or a curable resin that does not require transparency. Inaddition, when blended with a plasticizer, some excellent effects thatthe aggregates in the dispersion obtained are small in amounts, andtransparency and heat resistance are excellent are exhibited.

[Fine Cellulose Fiber Composite]

The fine cellulose fiber composite of the present invention has thefeature that the composite contains fine cellulose fibers and a polymerhaving an ethylene oxide/propylene oxide (EO/PO) copolymer moiety or apropylene oxide (PO) polymer moiety, the fine cellulose fibers beingconnected with the polymer via an amide bond. The phrase “ . . . and apolymer having an EO/PO copolymer moiety or a PO polymer moiety, . . .being connected with the polymer via an amide bond” as used herein meansa state in which carbon atoms of the amide group is covalently boundwith the cellulose backbone, so that a polymer having an EO/PO polymermoiety or a PO polymer moiety is covalently bound with a nitrogen atomdirectly or via a linking group. The fine cellulose fiber composite maysometimes be hereinafter referred to as a fine cellulose fiber compositeA.

The reasons why the resin composition containing a fine cellulose fibercomposite A of the present invention has excellent transparency andmechanical strength, and further has excellent heat resistance anddimensional stability depending upon the resins are considered to be asfollows. The fine cellulose fiber composite A of the present inventioncontains fine cellulose fibers and an amine having a specified polymerchain, the fine cellulose fiber being covalently bound with the amine ata an already existing carboxy group on the surface thereof, so thatdispersibility in the resin is increased due to repulsion caused bysteric repulsion of the cellulose fiber composites themselves having theabove ethylene oxide/propylene oxide (EO/PO) copolymer moiety or thepropylene oxide (PO) polymer moiety, and at the same time affinity tothe resin of the fine cellulose fiber composite itself is increased.Therefore, the dispersibility in the resin becomes excellent whenblended with the resin, whereby it is made possible that a resincomposition obtained has excellent mechanical strength while maintaininginherently owned transparency, and further improved heat resistance anddimensional stability depending upon the resins.

<Fine Cellulose Fibers>

(Average Fiber Size)

The average fiber size of the fine cellulose fibers constituting thefine cellulose fiber composite A usable in the present invention ispreferably 0.1 nm or more, more preferably 0.2 nm or more, even morepreferably 0.5 nm or more, even more preferably 0.8 nm or more, andstill even more preferably 1 nm or more, from the viewpoint of producinga fine cellulose fiber composite having an average fiber size that giveseven fiber sizes. Also, the average fiber size is preferably 200 nm orless, more preferably 100 nm or less, even more preferably 50 nm orless, even more preferably 20 nm or less, even more preferably 10 nm orless, and still even more preferably 5 nm or less, from the viewpoint ofsufficiently improving mechanical strength when contained in athermoplastic resin or curable resin to provide a resin composition(also referred to a composite material), and at the same timemaintaining transparency, so that the resin further has excellent heatresistance or dimensional stability (these may be simply collectivelyreferred to as mechanical strength or the like), depending upon theresins. Here, the average fiber size of the cellulose fibers as usedherein can be measured with an interatomic force microscope (AFM), andspecifically, the average fiber size can be measured in accordance witha method described in Examples set forth below. Generally, a minimumunit of cellulose nanofibers prepared from higher plants is packed innearly square form having sizes of 6×6 molecular chains, so that theheight analyzed in the image according to the AFM can be assumed to be awidth of the fibers.

(Carboxy Group Content)

The carboxy group content of the fine cellulose fibers is preferably 0.1mmol/g or more, more preferably 0.4 mmol/g or more, even more preferably0.6 mmol/g or more, and even more preferably 0.8 mmol/g or more, fromthe viewpoint of allowing to stably finely pulverize and allowing amideformation. In addition, the carboxy group content is preferably 3 mmol/gor less, more preferably 2 mmol/g or less, even more preferably 1.8mmol/g or less, and even more preferably 1.5 mmol/g or less, from theviewpoint of improving handling property. Fine cellulose fibers of whichcarboxy group content is outside the above range may be contained in thefine cellulose fibers used in the present invention as impuritiesunintentionally. Here, the term “carboxy group content” means a totalamount of carboxy groups in the celluloses constituting the finecellulose fibers, and specifically measured in accordance with a methoddescribed in Examples set forth below.

(Average Aspect Ratio)

The average aspect ratio (fiber length/fiber size) of the fine cellulosefibers is preferably 10 or more, more preferably 20 or more, even morepreferably 50 or more, and still even more preferably 100 or more, fromthe viewpoint of sufficiently improving mechanical strength whencontained in a resin to provide a composite material. In addition, theaverage aspect ratio is preferably 1,000 or less, more preferably 500 orless, even more preferably 400 or less, and still even more preferably350 or less, from the viewpoint of inhibiting the lowering of themechanical strength that accompanies the lowering of dispersibility inthe resin. The fine cellulose fibers of which average aspect ratio iswithin the above range have excellent dispersibility in a resin and highmechanical strength when the fine cellulose fibers are blended in theresin, so that a resin composition which is hardly likely to undergobrittle fracture is obtained. Here, the average aspect ratio as usedherein is obtained by taking an inverse of the aspect ratio of thecellulose fibers according to the following formula (1), from therelationship between a cellulose fiber concentration in the dispersionand a specific viscosity against water of the dispersion. Here, thefollowing formula (1) is derived from viscosity equation (8.138) of arigid rod-shape molecule described in The Theory of Polymer Dynamics, M.DOI and D. F. EDWARDS, CLARENDON PRESS•OXFORD, 1986, P312 and a relationof Lb²×ρ=M/N_(A), wherein Lisa fiber length, b is a fiber width(assuming that a cross section of the cellulose fibers is a square), ρis a concentration of the cellulose fibers (kg/m³), M is a molecularweight, and N_(A) is an Avogadro number. In addition, in the aboveviscosity formula (8.138), the rigid rod-shaped molecule is assumed ascellulose fibers. In the following formula (1), η_(SP) is a specificviscosity, π is a ratio of the circumference to a diameter, ln is anatural logarithm, P is an aspect ratio (L/b), γ=0.8, ρ_(S) is a densityof a dispersion medium (kg/m³), ρ₀ is a density of cellulose crystals(kg/m³), and C is a mass concentration of cellulose (C=ρ/ρ_(S)).

$\begin{matrix}{\eta_{sp} = {\frac{2\; \pi \; P^{2}}{45\left( {{\ln \; P} - \gamma} \right)} \times \frac{\rho_{s}}{\rho_{0}} \times C}} & (1)\end{matrix}$

(Crystallinity)

The crystallinity of the fine cellulose fibers is preferably 30% ormore, more preferably 35% or more, even more preferably 40% or more, andstill even more preferably 45% or more, from the viewpoint of improvingmechanical strength when contained in a resin to form a compositematerial. In addition, the crystallinity is preferably 95% or less, morepreferably 90% or less, even more preferably 85% or less, and still evenmore preferably 80% or less, from the viewpoint of improving reactionefficiency of amide-formation reaction. The crystallinity of thecellulose as used herein is a cellulose I crystallinity calculatedaccording to Segal method from diffraction intensity values according toX-ray diffraction method, which is defined by the following calculationformula (A):

Cellulose I Crystallinity (%)=[(I22.6−I18.5)/I22.6]×100  (A)

wherein I22.6 is a diffraction intensity of a lattice face (face 002)(angle of diffraction 2θ=22.6°), and I18.5 is a diffraction intensity ofan amorphous portion (angle of diffraction 2θ=18.5°), in X-raydiffraction. Here, cellulose I is a crystalline form of a naturalcellulose, and the cellulose I crystallinity means a proportion of theamount of crystalline region that occupies the entire cellulose.

<Amine Having EO/PO Copolymer Moiety or PO Polymer Moiety>

In the fine cellulose fiber composite A of the present invention, theabove fine cellulose fibers are connected with a polymer having an EO/POcopolymer moiety or a PO polymer moiety via an amide bond. Accordingly,in the present invention, the amine having an EO/PO copolymer moiety ora PO polymer moiety may be bound with a carboxy group of the above finecellulose fibers via an amide bond, and the amine may be any one of aprimary amine and a secondary amine, and a primary amine is preferred,from the viewpoint of reactivity with an amide bond.

(EO/PO Copolymer Moiety or PO Polymer Moiety)

The EO/PO copolymer moiety means a structure in which ethylene oxides(EO) and propylene oxides (PO) are polymerized in a random or blockform, and the PO polymer moiety means a chain structure in whichpropylene oxides (PO) are polymerized. For example, when an amine havingan EO/PO copolymer moiety or a PO polymer moiety is represented by theformula (i) given later, the ethylene oxides (EO) and the propyleneoxides (PO) form a chain structure of a random or block form, and whenan amine has a structure represented by the formula (ii) given later,(EO)a(PO)b, (EO)c(PO)d, and (EO)e(PO)f do not need to be in chain form.

The molecular weight of the EO/PO copolymer moiety or the PO polymermoiety is preferably 500 or more, more preferably 700 or more, even morepreferably 1,000 or more, and even more preferably 1,500 or more, fromthe viewpoint of providing a resin composition having smaller amounts ofaggregates in the dispersion obtained and having excellent transparencyand heat resistance when blended with a plasticizer, and also havingexcellent mechanical strength or the like when blended in the resin.From the same viewpoint, the molecular weight is preferably 10,000 orless, more preferably 7,000 or less, even more preferably 5,000 or less,even more preferably 4,000 or less, even more preferably 3,500 or less,and still even more preferably 2,500 or less. The molecular weight canbe obtained by calculating from an average number of moles added when anamine is produced. For example, in a case of an amine having a structurerepresented by the formula (ii) given later, a total of the molecularweights of (EO)a(PO)b+(EO)c(PO)d+(EO)e(PO)f is defined as a molecularweight of the EO/PO copolymer moiety.

The PO content ratio (% by mol) in the EO/PO copolymer moiety ispreferably 1% by mol or more, more preferably 6% by mol or more, andeven more preferably 8% by mol or more, from the viewpoint of providinga resin composition having smaller amounts of aggregates in thedispersion obtained and having excellent transparency and heatresistance when blended with a plasticizer, and also having excellentmechanical strength or the like when blended in the resin. From the sameviewpoint, the content ratio is preferably less than 100% by mol, morepreferably 99% by mol or less, even more preferably 90% by mol or less,even more preferably 80% by mol or less, even more preferably 74% by molor less, even more preferably 60% by mol or less, even more preferably51% by mol or less, even more preferably 40% by mol or less, and evenmore preferably 30% by mol or less. The PO content ratio (% by mol) ofthe EO/PO copolymer moiety can be obtained by calculating from anaverage number of moles added when an amine is produced.

It is preferable that the EO/PO copolymer moiety or the PO polymermoiety and the amine are bound directly or via a linking group. Thelinking group is preferably a hydrocarbon group, and an alkylene grouphaving the number of carbon atoms of preferably from 1 to 6, morepreferably from 1 to 3, is used. For example, an ethylene group or apropylene group is preferred.

The amine having an EO/PO copolymer moiety or a PO polymer moietyincludes, for example, a compound represented by the following formula(i):

wherein R₁ is a hydrogen atom, a linear or branched alkyl group havingfrom 1 to 6 carbon atoms, a —CH₂CH(CH₃)NH₂ group, or a group representedby the following formula (ii); EO and PO are present in a random orblock form; a is 0 or a positive number showing an average number ofmoles of EO added; and b is a positive number showing an average numberof moles of PO added,

wherein the formula (ii) is:

wherein n is 0 or 1; R₂ is a phenyl group, a hydrogen atom, or a linearor branched alkyl group having from 1 to 3 carbon atoms; EO and PO arepresent in a random or block form; c and e show an average number ofmoles of EO added, which is independently a number of from 0 to 50; andd and f show an average number of moles of PO added, which isindependently a number of from 1 to 50.

In a case of an amine having a PO polymer moiety, a in the formula (i)is 0. On the other hand, in a case of an amine having an EO/PO copolymermoiety, a in the formula (i) is preferably exceeding 0, more preferably1 or more, even more preferably 5 or more, even more preferably 10 ormore, even more preferably 15 or more, even more preferably 20 or more,and even more preferably 25 or more, from the viewpoint of providing aresin composition having smaller amounts of aggregates in the dispersionobtained and having excellent transparency and heat resistance whenblended with a plasticizer, and also having excellent mechanicalstrength or the like when blended in the resin. From the same viewpoint,it is preferably 100 or less, more preferably 80 or less, even morepreferably 60 or less, and even more preferably 45 or less.

In a case of an amine having a PO polymer moiety, b in the formula (i)is preferably 9 or more, more preferably 12 or more, even morepreferably 17 or more, and still even more preferably 26 or more, fromthe viewpoint of providing a resin composition having smaller amounts ofaggregates in the dispersion obtained and having excellent transparencyand heat resistance when blended with a plasticizer, and also havingexcellent mechanical strength or the like when blended in the resin.From the same viewpoint, it is preferably 175 or less, more preferably120 or less, even more preferably 80 or less, even more preferably 70 orless, even more preferably 60 or less, and still even more preferably 44or less.

In a case of an amine having an EO/PO polymer moiety, b in the formula(i) is preferably 1 or more, more preferably 2 or more, and even morepreferably 3 or more, from the same viewpoint as above. It is preferably100 or less, more preferably 70 or less, even more preferably 50 orless, even more preferably 30 or less, even more preferably 25 or less,even more preferably 20 or less, and still even more preferably 12 orless, from the same viewpoint.

In addition, as to the PO content ratio (% by mol) in the EO/POcopolymer moiety, when an amine is represented by the formula (i)defined above, the PO content ratio in the copolymer moiety can becalculated from a and b mentioned above, which can be obtained by theformula: b×100/(a+b). When an amine is represented by the formula (i)and the formula (ii) defined above, the content ratio can be similarlycalculated by the formula: (b+d+f)×100/(a+b+c+d+e+f). The preferredranges are as mentioned above.

R₁ in the formula (i) is a hydrogen atom, a linear or branched alkylgroup having from 1 to 6 carbon atoms, a —CH₂CH(CH₃)NH₂ group, or agroup represented by the formula (ii) defined above, and a hydrogen atomis preferred, from the viewpoint of providing a resin composition havingsmaller amounts of aggregates in the dispersion obtained and havingexcellent transparency and heat resistance, and also having excellentmechanical strength or the like when blended in the resin. The linear orbranched alkyl group having from 1 to 6 carbon atoms is preferably amethyl group, an ethyl group, and an iso- or normal-propyl group.

In addition, when R₁ in the formula (i) is a group represented by theformula (ii), the linear or branched alkyl group having from 1 to 3carbon atoms of R₂ in the formula (ii) is preferably a methyl group andan ethyl group. When R₂ is a methyl group or an ethyl group, it ispreferable that n is 1, and when R₂ is a hydrogen atom, it is preferablethat n is 0. In addition, c and e in the formula (ii) are independentlypreferably from 10 to 30, and d and f are independently preferably from5 to 25.

The amine having an EO/PO copolymer moiety or a PO polymer moietyrepresented by the formula (i) can be prepared in accordance with aknown method. For example, ethylene oxides and propylene oxides may beadded in desired amounts to a propylene glycol alkyl ether, andthereafter a hydroxyl group terminal may be formed into an amino group.The alkyl ether may be opened with an acid as needed so as to have ahydrogen atom at a terminal. For these production methods, JapanesePatent Laid-Open No. Hei-3-181448 can be referred.

In addition, commercially available products are suitably used, andspecific examples include Jeffamine M-2070, Jeffamine M-2005, JeffamineM-1000, Surfoamine B200, Surfoamine L100, Surfoamine L200, SurfoamineL207, Surfoamine L300, XTJ-501, XTJ-506, XTJ-507, XTJ-508 manufacturedby HUNTSMAN; M3000 manufactured by BASF, Jeffamine ED-900, JeffamineED-2003, Jeffamine D-2000, Jeffamine D-4000, XTJ-510, Jeffamine T-3000,Jeffamine T-5000, XTJ-502, XTJ-509, XTJ-510 and the like. These can beused alone or in a combination of two or more kinds.

The binding amount of the amide groups having an EO/PO copolymer moietyor a PO polymer moiety in the fine cellulose fiber composite A ispreferably 0.01 mmol/g or more, more preferably 0.05 mmol/g or more,even more preferably 0.1 mmol/g or more, and even more preferably 0.2mmol/g or more, from the viewpoint of providing a resin compositionhaving smaller amounts of aggregates in the dispersion obtained andhaving excellent transparency and heat resistance when blended with aplasticizer, and also having excellent mechanical strength or the likewhen blended in the resin. In addition, the binding amount is preferably3 mmol/g or less, more preferably 2 mmol/g or less, even more preferably1 mmol/g or less, and even more preferably 0.5 mmol/g or less, from theviewpoint of reactivity upon connecting via an amide bond. The bindingamount of the amide group having an EO/PO copolymer moiety or a POpolymer moiety can be adjusted by changing an amount of amine, the kindof amines, a reaction temperature, a reaction time, a solvent, or thelike.

In addition, the modification ratio of the amide group having an EO/POcopolymer moiety or a PO polymer moiety in the fine cellulose fibercomposite A (also referred to as amide-formation ratio) is preferably 1%or more, more preferably 5% or more, even more preferably 10% or more,even more preferably 15% or more, and even more preferably 20% or more,from the viewpoint of providing a resin composition having smalleramounts of aggregates in the dispersion obtained and having excellenttransparency and heat resistance when blended with a plasticizer, andalso having excellent transparency and mechanical strength when blendedin the resin. In addition, the modification ratio is preferably 90% orless, more preferably 70% or less, even more preferably 50% or less, andeven more preferably 40% or less, from the viewpoint of reactivity.Here, the binding amount (mmol/g) and the modification ratio (%) of theamide group having an EO/PO copolymer moiety or a PO polymer moiety asused herein are specifically obtained by a method described in Examplesset forth below.

<Method for Producing Fine Cellulose Fiber Composite A>

The fine cellulose fiber composite A can be produced in accordance witha known method without particular limitations, so long as an EO/POcopolymer moiety or a PO polymer moiety can be introduced via an amidegroup to fine cellulose fibers. For example, a reaction of introducingan EO/PO copolymer moiety or a PO polymer moiety to previously preparedfine cellulose fibers via an amide group may be carried out, or areaction of, subsequent to the preparation of fine cellulose fibers,introducing an EO/PO copolymer moiety or a PO polymer moiety via anamide group may be carried out. Here, fine cellulose fibers can beproduced according to a known method, for example, a method described inJapanese Patent Laid-Open No. 2011-140632.

Preferred methods for production include a production method includingthe following step (A) and step (B):

step (A): oxidizing natural cellulose fibers in the presence of anN-oxyl compound, to provide carboxy group-containing cellulose fibers;andstep (B): subjecting the carboxy group-containing cellulose fibersobtained in the step (A) and an amine having an EO/PO copolymer moietyor a PO polymer moiety to an amide-formation reaction.Here, preferred production methods mentioned above include a methodincluding, subsequent to the step (A), carrying out a finely pulverizingstep, to provide carboxy-group containing fine cellulose fibers, andthereafter carrying out the step (B) (Production Embodiment 1A); and amethod including, subsequent to the step (A), carrying out the step (B),and then carrying out a finely pulverizing step (Production Embodiment2A).

The method for producing a fine cellulose fiber composite A will beexplained hereinafter on the basis of “Production Embodiment 1A”mentioned above.

[Step (A)]

The step (A) is a step of oxidizing natural cellulose fibers in thepresence of an N-oxyl compound, to provide carboxy group-containingcellulose fibers.

In the step (A), first, a slurry of natural cellulose fibers dispersedin water is prepared. The slurry is obtained by adding water in anamount of about 10 to about 1,000 times the amount on mass basis basedon the raw material natural cellulose fibers (on absolute dry basis: themass of natural cellulose fibers after subjection to thermal drying at150° C. for 30 minutes), and treating the mixture with a mixer or thelike. The natural cellulose fibers include, for example, wooden pulpsuch as pulp from needle-leaf trees and pulp from broad-leaf trees;cotton pulp such as cotton linter and cotton lint; non-wooden pulp suchas maize straw pulp and bagasse pulp; bacteria cellulose; and the like.These natural cellulose fibers can be used alone or in a combination oftwo or more kinds. The natural cellulose fibers may be subjected to atreatment of increasing surface areas such as treatment with a beater.In addition, the cellulose I crystallinity of the above-mentionedcommercially available pulp is usually 80% or more.

(Oxidization Treatment Step)

Next, the above-mentioned natural cellulose fibers are subjected to anoxidation treatment in the presence of an N-oxyl compound to providecarboxy group-containing cellulose fibers, which may be hereinaftersimply referred to as “oxidation treatment.”

As the N-oxyl compound, one or more heterocyclic N-oxyl compoundsselected from piperidinoxyl compounds, pyrrolidinoxyl compounds,imidazolinoxyl compounds, and azaadamantane compounds having an alkylgroup having 1 or 2 carbon atoms are preferred. Among them, thepiperidinoxyl compounds having an alkyl group having 1 or 2 carbon atomsare preferred, from the viewpoint of reactivity, which includesdi-tert-alkylnitroxyl compounds such as a2,2,6,6-tetraalkylpiperidin-1-oxyl (TEMPO), a4-hydroxy-2,2,6,6-tetraalkylpiperidin-1-oxyl, a4-alkoxy-2,2,6,6-tetraalkylpiperidin-1-oxyl, a4-benzoyloxy-2,2,6,6-tetraalkylpiperidin-1-oxyl, a4-amino-2,2,6,6-tetraalkylpiperidin-1-oxyl; a 4-acetamide-TEMPO, a4-carboxy-TEMPO, a 4-phosphonoxy-TEMPO, and the like. Among thesepiperidinoxyl compounds, a 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO),a 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, and a4-methoxy-2,2,6,6-tetramethylpiperidin-1-oxyl are more preferred, and a2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) is even more preferred.

The amount of the N-oxyl compound may be a catalytic amount, and theamount is preferably from 0.001 to 10% by mass, more preferably from0.01 to 9% by mass, even more preferably from 0.1 to 8% by mass, andstill even more preferably from 0.5 to 5% by mass, based on the naturalcellulose fibers, on absolute dry basis.

In the oxidation treatment of the natural cellulose fibers, an oxidizingagent can be used. The oxidizing agent includes oxygen or the air,peroxides, halogens, hypohalous acids, halous acids, perhalo acid, andalkali metal salts or alkaline earth metal salts thereof, halogenoxides, nitrogen oxide, and the like, from the viewpoint of solubility,reaction rate or the like when a solvent is adjusted to an alkalineregion. Among them, an alkali metal hypohalite is preferred, which isspecifically exemplified by sodium hypochlorite and sodium hypobromite.The amount of the oxidizing agent used may be selected in accordancewith the carboxy group substitution degree (oxidation degree) of thenatural cellulose fibers, and the amount of the oxidizing agent used isnot unconditionally determined because the yields of the oxidationreaction differ depending upon the reaction conditions. The amount iswithin the range of from about 1 to about 100% by mass, based on the rawmaterial natural cellulose fibers, on absolute dry basis.

In addition, in order to even more efficiently carry out the oxidationreaction, a bromide such as sodium bromide or potassium bromide, or aniodide such as sodium iodide or potassium iodide can be used as apromoter. The amount of the promoter may be an effective amount that canexhibit its function, without particular limitations.

The reaction temperature in the oxidation treatment is preferably 50° C.or lower, more preferably 40° C. or lower, and even more preferably 20°C. or lower, from the viewpoint of selectivity of the reaction andsuppression of side reaction, and the lower limit of the reactiontemperature is preferably −5° C. or higher.

In addition, it is preferable that a pH of the reaction system matcheswith the property of the oxidizing agent; for example, when sodiumhypochlorite is used as an oxidizing agent, a pH of the reaction systemis preferably on an alkaline side, preferably a pH of from 7 to 13, andmore preferably a pH of from 10 to 13. Also, it is desired that areaction time is from 1 to 240 minutes.

By carrying out the above-mentioned oxidation treatment, carboxygroup-containing cellulose fibers having a carboxy group contentpreferably within the range of 0.1 mmol/g or more and 3 mmol/g or lessare obtained.

(Purifying Step)

The carboxy group-containing cellulose fibers obtainable by theabove-mentioned oxidation reaction contain an N-oxyl compound such asTEMPO used as a catalyst, or a by-product salt. The carboxygroup-containing cellulose fibers may be subjected to the subsequentsteps without any treatments, or the cellulose fibers may be subjectedto purification, whereby carboxy group-containing cellulose fibershaving a high purity can be obtained. As a purification method, anoptimal method can be employed according to the kinds of the solvents inthe oxidation reaction, the degree of oxidation of the product, and thedegree of purification. For example, the purification method includesre-precipitation with a well dissolvable solvent water and a hardlydissolvable solvent such as methanol, ethanol, or acetone, extraction ofTEMPO or the like to a solvent that allows phase separation with water,such as hexane, and other purifications such as ion-exchange of saltsand dialysis.

(Finely Pulverizing Step)

In Production Embodiment 1A, after the above-mentioned purifying step, astep of finely pulverizing the carboxy group-containing cellulose fibersobtained in the step (A) is carried out. In the finely pulverizing step,it is preferable that the carboxy group-containing cellulose fibersobtained through the above-mentioned purifying step are dispersed in asolvent, and subjected to a finely pulverizing treatment. By carryingout this finely pulverizing step, fine cellulose fibers having anaverage fiber size and an average aspect ratio respectively within theranges mentioned above are obtained.

The solvent used as a dispersion medium is exemplified by water, analcohol having from 1 to 6 carbon atoms, and preferably from 1 to 3carbon atoms, such as methanol, ethanol, or propanol, a ketone havingfrom 3 to 6 carbon atoms, such as acetone, methyl ethyl ketone or methylisobutyl ketone, a linear or branched saturated hydrocarbon orunsaturated hydrocarbon having from 1 to 6 carbon atoms, an aromatichydrocarbon such as benzene or toluene, a halogenated hydrocarbon suchas methylene chloride or chloroform, a lower alkyl ether having from 2to 5 carbon atoms, a polar solvent such as N,N-dimethylformamide,N,N-dimethylacetamide, dimethyl sulfoxide, or a diester obtained fromsuccinic acid and triethylene glycol monomethyl ether, and the like.These solvents can be used alone or in a mixture of two or more kinds.The solvent is preferably water, an alcohol having from 1 to 6 carbonatoms, a ketone having from 3 to 6 carbon atoms, a lower alkyl etherhaving from 2 to 5 carbon atoms, or a polar solvent such asN,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, ormethyl triglycol succinate diester, from the viewpoint of operability ofthe finely pulverizing treatment, and more preferably water, from theviewpoint of environmental friendliness. The amount of the solvent usedmay be an effective amount that can disperse the carboxygroup-containing cellulose fibers, without particular limitations. Thesolvent is used in an amount of preferably from 1 to 500 times the mass,and more preferably from 2 to 200 times the mass, based on the carboxygroup-containing cellulose fibers.

In addition, as an apparatus to be used in the finely pulverizingtreatment, a known dispersing machine is suitably used. For example,disintegrator, a beating machine, a low-pressure homogenizer, ahigh-pressure homogenizer, a grinder, a cutter mill, a ball-mill, a jetmill, a short shaft extruder, a twin-screw extruder, an ultrasonicagitator, a juice mixer for households, or the like can be used. Inaddition, the solid content concentration of the reaction product fibersin the finely pulverizing treatment is preferably 50% by mass or less.

The form of the carboxy group-containing fine cellulose fibersobtainable after the finely pulverizing step can be, as occasiondemands, in the form of a suspension of which solid contentconcentration is adjusted, e.g. visually colorless transparent or opaqueliquid, or in the form of powder subjected to a drying treatment,provided that it is intended to mean that the fine cellulose fibers arein the form of an aggregated powder, not cellulose particles. Here, whenprovided in the form of a suspension, as a dispersion medium, wateralone may be used, or a mixed solvent of water with other organicsolvent, e.g. an alcohol such as ethanol, a surfactant, an acid, a baseor the like may be used.

By subjecting the natural cellulose fibers to the oxidation treatmentand the finely pulverizing treatment as described above, hydroxyl groupsat a C6-position of the cellulose constituting unit are selectivelyoxidized to carboxy groups via aldehyde groups, and cellulose fibersbeing composed of cellulose having the above-mentioned carboxy groupcontent of preferably from 0.1 to 3 mmol/g, and preferably cellulosefibers being finely pulverized to an average fiber size of from 0.1 to200 nm, having a crystallinity of preferably 30% or more, can beobtained. The above-mentioned carboxy group-containing fine cellulosefibers have a cellulose I crystal structure. This means that the carboxygroup-containing fine cellulose fibers used in the present invention arefibers prepared by subjecting cellulose solid raw materials derived fromnature having a cellulose I crystal structure to surface oxidation andfinely pulverizing treatment. Here, in the step (A), after the oxidationtreatment of the natural cellulose fibers, further an acid, e.g.hydrochloric acid, is allowed to react, so that a carboxy group contentcan be adjusted, and the reaction may be carried out before the finelypulverizing treatment or after the finely pulverizing treatment.

[Step (B)]

In Production Embodiment 1A, the step (B) is a step of subjecting thecarboxy group-containing fine cellulose fibers obtained through theabove-mentioned finely pulverizing step and an amine having an EO/POcopolymer moiety or a PO polymer moiety to an amide formation reaction,to provide a fine cellulose fiber composite. Specifically, a carboxygroup contained in the carboxy group-containing fine cellulose fibersand an amino group of the amine having an EO/PO copolymer moiety or a POpolymer moiety are subjected to a condensation reaction to form an amidebond, to provide a fine cellulose fiber composite with which the EO/POcopolymer moiety or the PO polymer moiety is connected via an amidebond.

The amine having an EO/PO copolymer moiety or a PO polymer moiety usablein the step (B) includes those that are mentioned above in the finecellulose fiber composite A.

The amount of the above amine used is an amount such that the aminegroups, based on one mol of the carboxy groups contained in the carboxygroup-containing fine cellulose fibers are used in an amount ofpreferably 0.1 mol or more, more preferably 0.5 mol or more, even morepreferably 0.7 mol or more, and still even more preferably 1 mol ormore, from the viewpoint of reactivity, and the amine groups are used inan amount of preferably 50 mol or less, more preferably 20 mol or less,and even more preferably 10 mol or less, from the viewpoint ofmanufactured article purity. Here, the amines in the amount contained inthe above range may be supplied to the reaction at once, or may besupplied in divided portions. When the amine is a monoamine, the aboveamine groups are the same as the amine.

In the reaction of the above carboxy group-containing fine cellulosefibers with the above amine (which may be hereinafter referred to as“condensation reaction” or “amide bond formation reaction” in somecases), a known condensing agent can be used.

The condensing agent is not particularly limited, and includescondensing agents described in Gosei Kagaku Shirizu Pepuchido Gosei(Synthetic Chemistry Series Peptide Synthesis) (Maruzen Publishing),page 116, or described in Tetrahedron, 57, 1551(2001), and the like. Thecondensing agent includes, for example,4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (maybe hereinafter referred to as “DMT-MM” in some cases), and the like.

In the above condensation reaction, a solvent includes the solvent inthe above finely pulverizing step, and it is preferable to select asolvent that dissolves an amine used.

The reaction time and the reaction temperature in the above condensationreaction can be appropriately selected in accordance with the amine usedand the kinds of the solvents and the like. The reaction time ispreferably from 1 to 24 hours, and more preferably from 10 to 20 hours,from the viewpoint of reaction rate. Also, the reaction temperature ispreferably 0° C. or higher, more preferably 5° C. or higher, and evenmore preferably 10° C. or higher, from the viewpoint of reactivity. Inaddition, the reaction temperature is preferably 200° C. or lower, morepreferably 80° C. or lower, and even more preferably 30° C. or lower,from the viewpoint of the coloration of the composite.

After the reaction, post-treatments may be appropriately carried out inorder to remove unreacted amines, the condensing agent, and the like. Asthe method for post-treatments, for example, filtration, centrifugation,dialysis, or the like can be used.

In Production Embodiment 2A, the same method as in Production Embodiment1A can be carried out except for carrying out each of the above steps inthe order of the step (A), the step (B), and the finely pulverizingstep.

The fine cellulose fiber composite A thus obtained can be used in thestate of a dispersion after subjecting to the post-treatment mentionedabove, or alternatively is subjected to a drying treatment or the liketo remove the solvents from the dispersion, to provide a fine cellulosefiber composite in a dry powdery state, and this dry powder can also beused. The term “powdery state” as used herein is a powdery state inwhich the fine cellulose fiber composites are aggregated, and does notmean cellulose particles.

The fine cellulose fiber composite A in a powdery state includes, forexample, a dried product obtained by directly drying a dispersion of theabove-mentioned fine cellulose fiber composite A; a powdered productobtained by a mechanical treatment of the dried product; a powderedproduct obtained by powdering a dispersion of the above-mentioned finecellulose fiber composite A according to a known spray-drying method; apowdered product obtained by powdering a dispersion of theabove-mentioned fine cellulose fiber composite A according to a knownfreeze-drying method; and the like. The above spray-drying method is amethod including spraying the above-mentioned dispersion of a finecellulose fiber composite A in the air, and drying the dispersion.

The average fiber size of the fine cellulose fiber composite A ispreferably 0.1 nm or more, more preferably 0.2 nm or more, even morepreferably 0.5 nm or more, even more preferably 0.8 nm or more, andstill even more preferably 1 nm or more, from the viewpoint of heatresistance, i.e. a less degree of coloration upon molding. In addition,the average fiber size is preferably 200 nm or less, more preferably 100nm or less, even more preferably 50 nm or less, even more preferably 20nm or less, and still even more preferably 10 nm or less, from theviewpoint of mechanical strength and transparency.

Here, since the fine cellulose fiber composite A does not undergolowering of crystallinity by the reaction of the step (B), it ispreferable that the fine cellulose fiber composite has a crystallinityof the same level as the crystallinity of the above-mentioned finecellulose fibers.

The fine cellulose fiber composite A contained in the resin compositionof the present invention is one in which fine cellulose fibers areconnected with an EO/PO copolymer moiety or a PO polymer moiety via anamide bond as mentioned above, and those having an average fiber size offrom 0.1 to 200 nm are preferred.

The fine cellulose fiber composite contained in the resin composition ofthe present invention may be those in which the fine cellulose fibersare bound with an EO/PO copolymer moiety or a PO polymer moiety via anamide bond as mentioned above. Also, the present invention provides thefollowings as one embodiment of the above fine cellulose fibercomposite. In other words, the present invention provides the above finecellulose fiber composite in which the fine cellulose fibers are furtherbound with a specified cation and/or a functional group at a carboxygroup. More specifically, the present invention provides a finecellulose fiber composite wherein fine cellulose fibers are connectedwith a polymer having an ethylene oxide/propylene oxide (EO/PO)copolymer moiety or a propylene oxide (PO) polymer moiety via an amidebond, and wherein one or two bindings selected from the group consistingof the following (1) and (2) are further introduced.

(1) the binding via an ionic bond of a quaternary alkylammonium cationhaving a total number of carbon atoms of from 4 to 40; and(2) the binding via an amide bond of an aromatic hydrocarbon grouphaving a total number of carbon atoms of from 6 to 20.The fine cellulose fiber composite may also be hereinafter referred toas a fine cellulose fiber composite a.

In the present invention, since the EO/PO copolymer moiety or the POpolymer moiety is present on a surface of the cellulose fibers, thecellulose fiber composites themselves have increased dispersibility inthe resin due to repulsion caused by steric repulsion, and at the sametime affinity to the resin is increased. Further, because of thepresence of one or more members of a specified quaternary alkylammoniumcation and aromatic hydrocarbon groups, some effects are exhibited suchthat wettability of the cellulose fiber composite is even more improved,thereby making it possible to perform high-dispersion in the resin, andthat the mechanical strength is even more improved while maintaining thetransparency of the resin composition obtained, so that the cellulosefiber composite further has excellent heat resistance and dimensionalstability depending upon the resins. Here, in the present specification,the wettability shows compatibility with solvents and the resin, meaningthat the higher the wettability, the higher the compatibility.

In the fine cellulose fiber composite a, fine cellulose fibers and anamine having an EO/PO copolymer moiety or a PO polymer moiety used, anda method for introducing the amine to fine cellulose fibers are the sameas mentioned above.

In addition, upon binding of a specified cation and/or functional groupto the fine cellulose fibers, a known method can be used. For example,in the case of a quaternary alkylammonium cation, a quaternaryalkylammonium compound may be bound to form a salt, and in the case ofan aromatic hydrocarbon group, an amine having an aromatic hydrocarbongroup may be formed into an amide bonding. For the sake of convenience,the amine having an EO/PO copolymer moiety or a PO polymer moiety may bedescribed as a first amine, and a compound used in the bond of the above(1) and (2) may be described as a second amine hereinafter.

The binding of the fine cellulose fibers with a quaternary alkylammoniumcompound having a total number of carbon atoms of from 4 to 40 at acarboxy group as used herein means that the carboxy group isdeprotonated and at the same time forms a quaternary alkylammoniumcation, and those are in the state of ionic bond.

The four alkyl groups of the quaternary alkyl ammonium compound may beidentical or different, so long as a total number of carbon atoms isfrom 4 to 40, and the alkyl group may be substituted or unsubstituted.The alkyl group as used herein includes alkyl groups having from 1 to 20carbon atoms, and specific examples include, for example, a methylgroup, an ethyl group, a propyl group, a butyl group, a lauryl group, acetyl group, a stearyl group, a benzyl group, and a phenethyl group. Thetotal number of carbon atoms of these four alkyl groups may be 4 or moreand 40 or less, and preferably 8 or more, and more preferably 12 ormore, from the viewpoint of reactivity, and the total number of carbonatoms is preferably 36 or less, more preferably 32 or less, even morepreferably 24 or less, even more preferably 20 or less, and even morepreferably 18 or less, from the same viewpoint.

Specific examples of the quaternary alkylammonium compound having atotal number of carbon atoms of from 4 to 40 include tetramethylammoniumhydroxide, tetraethylammonium hydroxide, tetraethylammonium chloride,tetrabutylammonium hydroxide, tetrapropylammonium hydroxide,tetrabutylammonium chloride, lauryltrimethylammonium chloride,dilauryldimethyl chloride, stearyltrimethylammonium chloride,distearyldimethylammonium chloride, cetyltrimethylammonium chloride, andalkylbenzyldimethylammonium chloride. These quaternary alkylammoniumcompounds can be used alone or in a combination of two or more kinds.Among them, tetramethylammonium hydroxide, tetraethylammonium hydroxide,tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide arepreferred, from the viewpoint of reactivity. The quaternaryalkylammonium compound used in the present invention may be prepared inaccordance with a known method, or may be a commercially availableproduct.

In addition, the above fine cellulose fibers are bound with an aminehaving an aromatic hydrocarbon group having a total number of carbonatoms of 6 to 20 at a carboxy group as used herein means that a carboxygroup and the amine form an amide bond and are in the state of covalentbonding.

The amine having an aromatic hydrocarbon group may be those having atotal number of carbon atoms of from 6 to 20, which may be any ofprimary amines and secondary amines, and the primary amines arepreferred, from the viewpoint of reactivity with a carboxy group. Inaddition, the number of the aromatic hydrocarbon groups in the amine maybe one or two, so long as a total number of carbon atoms is from 6 to20, and one is preferred.

The amine having an aromatic hydrocarbon group includes an amine havingan aryl group and an amine having an aralkyl group, and the amine havingan aryl group is preferred, from the viewpoint of compatibility with theresin.

A total of the number of carbon atoms of the amine having an aromatichydrocarbon group is 6 or more and 20 or less, and the total ispreferably 18 or less, and more preferably 12 or less, from theviewpoint of compatibility with the resin. In the case of an aminehaving an aryl group, a total number of carbon atoms is 6 or more, andthe total number is 20 or less, preferably 14 or less, more preferably10 or less, and even more preferably 8 or less, from the viewpoint ofcompatibility with the resin. In the case of an amine having an aralkylgroup, a total number of carbon atoms is 7 or more, and the total numberis 20 or less, preferably 13 or less, more preferably 11 or less, andeven more preferably 9 or less, from the viewpoint of compatibility withthe resin.

Specific examples of the aryl group include a phenyl group, a naphthylgroup, an anthryl group, a phenanthryl group, a biphenyl group, and atriphenyl group. These aryl groups may be bound alone or in acombination of two or more of them. Among them, a phenyl group, anaphthyl group and a biphenyl group are preferred, and a phenyl group ismore preferred, from the viewpoint of compatibility with the resin.

Specific examples of the aralkyl group include a benzyl group, aphenethyl group, a phenylpropyl group, a phenylpentyl group, aphenylhexyl group, and a phenylheptyl group, and these aralkyl groupsmay be bound alone or in a combination of two or more of them. Amongthem, a benzyl group, a phenethyl group, a phenylpropyl group, aphenylpentyl group, and a phenylhexyl group are preferred, and a benzylgroup, a phenethyl group, a phenylpropyl group, and a phenylpentyl groupare more preferred, from the viewpoint of compatibility with the resin.

In addition, the above aryl group or aralkyl group may have asubstituent. The substituent includes, for example, alkyl groups havingfrom 1 to 6 carbon atoms, such as a methyl group, an ethyl group, apropyl group, an isopropyl group, a butyl group, an isobutyl group, asec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group,and a hexyl group; alkoxy groups having from 1 to 6 carbon atoms, suchas a methoxy group, an ethoxy group, a propoxy group, an isopropoxygroup, a butoxy group, an isobutoxy group, a sec-butoxy group, atert-butoxy group, a pentyloxy group, an isopentyloxy group, and ahexyloxy group; alkoxycarbonyl groups having from 1 to 6 carbon atoms,such as a methoxycarbonyl group, an ethoxycarbonyl group, apropoxycarbonyl group, an isopropoxycarbonyl group, a butoxycarbonylgroup, an isobutoxycarbonyl group, a sec-butoxycarbonyl group, atert-butoxycarbonyl group, a pentyloxycarbonyl group, and anisopentyloxycarbonyl group; halogen atoms such as a fluorine atom, achlorine atom, a bromine atom, and an iodine atom; acyl groups havingfrom 1 to 6 carbon atoms, aralkyl groups, and aralkyloxy groups.

Specific examples of the amine having the above aromatic hydrocarbongroup include amines having an aryl group, such as aniline, toluylamine,4-biphenylylamine, diphenylamine, 2-aminonaphthalene, p-terephenylamine,2-aminoanthracene, and 2-aminoanthraquinone. Among them, aniline,toluylamine, 4-biphenylamine, diphenylamine, and 2-aminonaphthalene arepreferred, and aniline is more preferred, from the viewpoint ofcompatibility with the resin. The amine having an aralkyl group includesbenzylamine, phenethylamine, 3-phenylpropylamine, 5-phenylpentylamine,6-phenylhexylamine, 7-phenylheptylamine, and 8-phenyloctylamine. Amongthem, from the same viewpoint, benzylamine, phenethylamine,5-phenylpentylamine, 6-phenylhexylamine, and 7-phenylheptylamine arepreferred, benzylamine, phenethylamine, 3-phenylpropylamine,5-phenylpentylamine, and 6-phenylhexylamine are more preferred, andbenzylamine, phenethylamine, 3-phenylpropylamine, and5-phenylpentylamine are even more preferred. The amine having anaromatic hydrocarbon group used in the present invention may be preparedby a known method, or may be a commercially available product.

In the fine cellulose fiber composite a, in addition to the amine havingan EO/PO copolymer moiety or a PO polymer moiety, either one of aquaternary alkylammonium compound having a total number of carbon atomsof from 4 to 40 or an amine having an aromatic hydrocarbon group havinga total number of carbon atoms of from 6 to 20 may be bound, or each maybe bound alone, or may be bound together.

The binding amount of the amine having an EO/PO copolymer moiety or a POpolymer moiety, which is a first amine, in the fine cellulose fibercomposite a, is preferably 0.01 mmol/g or more, more preferably 0.03mmol/g or more, and even more preferably 0.05 mmol/g or more, from theviewpoint of providing a resin composition having a smaller amount ofaggregates in the dispersion obtained, and having excellent transparencywhen blended with a plasticizer or a solvent, and having excellentcompatibility with the resin, and having excellent transparency,mechanical strength, dimensional stability, and heat resistance whenblended with the resin. In addition, the binding amount is preferably 1mmol/g or less, more preferably 0.5 mmol/g or less, even more preferably0.25 mmol/g or less, even more preferably 0.1 mmol/g or less, even morepreferably 0.08 mmol/g or less, and even more preferably 0.06 mmol/g orless, from the same viewpoint and from the viewpoint of reactivity.Here, in the present invention, the binding amount of the first amine inthe fine cellulose fiber composite a can be measured in the same manneras in the first amine in the above fine cellulose fiber composite A, orthe binding amount may be obtained by IR measurement. Specifically, thebinding amount is obtained by a method described in Examples set forthbelow.

The binding amount of the second amine in the fine cellulose fibercomposite a is preferably 0.2 mmol/g or more, more preferably 0.3 mmol/gor more, even more preferably 0.5 mmol/g or more, even more preferably0.8 mmol/g or more, and even more preferably 1.0 mmol/g or more, fromthe viewpoint of transparency of the dispersion, from the viewpoint ofcompatibility with the resin, and from the viewpoint of transparency,mechanical strength, dimensional stability, and heat resistance of theresin composition. Also, the binding amount is preferably 1.5 mmol/g orless, more preferably 1.3 mmol/g or less, and even more preferably 1.2mmol/g or less, from the same viewpoint, and from the viewpoint ofreactivity when binding. The binding amount of the above amine can beadjusted by an amount of the amine, the kinds, a reaction temperature, areaction time, a solvent, or the like. Here, in the present inventionthe binding amount of the second amine refers to a total amount of thebinding amount of a quaternary alkylammonium compound having a totalnumber of carbon atoms of from 4 to 40 and the binding amount of theamine having an aromatic hydrocarbon group having a total number ofcarbon atoms of from 6 to 20, which can be obtained according to IRdetermination. Specifically, the binding amount is obtained inaccordance with a method described in Examples set forth below.

A total of the binding amount of the first amine and the binding amountof the second amine in the fine cellulose fiber composite a ispreferably 0.2 mmol/g or more, more preferably 0.3 mmol/g or more, evenmore preferably 0.5 mmol/g or more, even more preferably 0.8 mmol/g ormore, and even more preferably 1.0 mmol/g or more, from the viewpoint ofcompatibility with the resin, and from the viewpoint of transparency,mechanical strength, dimensional stability, and heat resistance of theresin composition. Also, a total of the binding amount is preferably 1.5mmol/g or less, more preferably 1.3 mmol/g or less, and even morepreferably 1.2 mmol/g or less, from the same viewpoint, and from theviewpoint of reactivity when binding.

The modification ratio of the EO/PO copolymer moiety or the PO polymermoiety in the fine cellulose fiber composite a is preferably 0.5% ormore, more preferably 1% or more, even more preferably 2% or more, andeven more preferably 5% or more, from the viewpoint of transparency ofthe dispersion, from the viewpoint of compatibility with the resin, andfrom the viewpoint of transparency, mechanical strength, dimensionalstability, and heat resistance of the resin composition. Also, themodification ratio is preferably 90% or less, more preferably 50% orless, even more preferably 20% or less, and even more preferably 10% orless, from the same viewpoint.

In addition, the modification ratio of the quaternary alkylammoniumcation and/or the aromatic hydrocarbon group in the fine cellulose fibercomposite a is preferably 10% or more, more preferably 20% or more, evenmore preferably 30% or more, even more preferably 40% or more, even morepreferably 50% or more, even more preferably 60% or more, and even morepreferably 70% or more, from the viewpoint of transparency of thedispersion, from the viewpoint of compatibility with the resin, and fromthe viewpoint of transparency, mechanical strength, dimensionalstability, and heat resistance of the resin composition. From the sameviewpoint, the modification ratio is preferably 90% or less, morepreferably 85% or less, and even more preferably 80% or less. Here, inthe present specification, the modification ratio (%) of the quaternaryalkylammonium cation and/or the aromatic hydrocarbon group is obtainedin accordance with a method described in Examples set forth below.

In addition, a total of the modification ratio of the first amine andthe modification ratio of the second amine in the fine cellulose fibercomposite a is preferably 10% or more, more preferably 20% or more, evenmore preferably 30% or more, even more preferably 40% or more, even morepreferably 50% or more, even more preferably 60% or more, even morepreferably 70% or more, even more preferably 75% or more, and even morepreferably 80% or more, from the viewpoint of having smaller amounts ofaggregates in the dispersion obtained, from the viewpoint oftransparency of the dispersion, and from the viewpoint of transparency,mechanical strength, dimensional stability, and heat resistance of theresin composition. From the same viewpoint, a total of the modificationratios is preferably 100% or less, more preferably 98% or less, evenmore preferably 95% or less, even more preferably 90% or less, and evenmore preferably 85% or less.

In the fine cellulose fiber composite a of the present invention, amolar ratio of the binding amount of the first amine to the bindingamount of the second amine (first amine/second amine) is preferably 0.01or more, and more preferably 0.03 or more, from the viewpoint ofcompatibility with the resin, from the viewpoint of transparency of thedispersion, and from the viewpoint of transparency, mechanical strength,dimensional stability, and heat resistance of the resin composition.From the same viewpoint, the molar ratio is preferably 0.4 or less, morepreferably 0.3 or less, even more preferably 0.2 or less, even morepreferably 0.1 or less, and even more preferably 0.05 or less.

In addition, when the quaternary alkylammonium compound and the aminehaving an aromatic hydrocarbon group are used together as the secondamines, a molar ratio of the binding amounts thereof (quaternaryalkylammonium compound/amine having aromatic hydrocarbon group) ispreferably 0.1 or more, more preferably 0.2 or more, and even morepreferably 0.4 or more, from the viewpoint of compatibility with theresin, from the viewpoint of transparency of the dispersion, and fromthe viewpoint of transparency, mechanical strength, dimensionalstability, and heat resistance of the resin composition. From the sameviewpoint, the molar ratio is preferably 0.9 or less, more preferably0.8 or less, and even more preferably 0.6 or less.

The introduction of the quaternary alkylammonium compound and the aminehaving an aromatic hydrocarbon group into the fine cellulose fibers canbe carried out in accordance with a known method without particularlimitations, and the order of introduction is such that any one of theabove introduction or the introduction of the amine having an EO/POcopolymer moiety or a PO polymer moiety may be carried out first. It ispreferable that the quaternary alkylammonium compound and the aminehaving an aromatic hydrocarbon group are introduced first, from theviewpoint of reactivity.

<Method for Producing Fine Cellulose Fiber Composite a>

The fine cellulose fiber composite a can be produced in accordance witha known method without particular limitations, so long as a quaternaryalkylammonium cation and/or an aromatic hydrocarbon group and an EO/POcopolymer moiety or a PO polymer moiety can be introduced into finecellulose fibers. For example, a reaction including introducing aquaternary alkylammonium cation via an ionic bond, and/or introducing anaromatic hydrocarbon group via an amide bond into previously preparedfine cellulose fibers, and thereafter introducing an EO/PO copolymermoiety or a PO polymer moiety thereinto via an amide bond may be carriedout, or a reaction including introducing the above may be carried outsubsequent to the preparation of the fine cellulose fibers. The finecellulose fibers can be produced in the same manner as mentioned above.

Accordingly, preferred methods for producing a fine cellulose fibercomposite a include, for example, a method including the following steps(a), (b-1), and (b-2):

step (a): oxidizing natural cellulose fibers in the presence of anN-oxyl compound, to provide carboxy group-containing cellulose fibers;andstep (b-1): mixing the carboxy group-containing cellulose fibersobtained in the step (a) and a quaternary alkylammonium compound, andsubjecting them to an amide-formation reaction with an amine having anaromatic hydrocarbon group, or carrying out only one of the above, toprovide cellulose fibers with which a quaternary alkylammonium cationand/or an aromatic hydrocarbon group is bound; andstep (b-2): subjecting the cellulose fibers obtained in the step (b-1)and an amine having an EO/PO copolymer moiety or a PO polymer moiety toan amide-formation reaction.

Here, the above preferred production methods include a method including,subsequent to the step (a), carrying out a finely pulverizing stepmentioned above, to provide carboxy group-containing fine cellulosefibers, and thereafter carrying out steps (b-1) and (b-2) (ProductionEmbodiment 1a); and a method including, subsequent to the step (a),carrying out the steps (b-1) and (b-2), and thereafter carrying out afinely pulverizing step (Production Embodiment 2a).

The method for producing a fine cellulose fiber composite will beexplained hereinbelow on the basis of “Production Embodiment 1a”mentioned above.

[Step (a)]

The step (a) is a step of oxidizing natural cellulose fibers in thepresence of an N-oxyl compound, to provide carboxy group-containingcellulose fibers, and the step can be carried out in reference to thestep (A) in the above “Production Embodiment 1A.” In addition, thepurifying step and the finely pulverizing step can be also carried outin the same manner referring to the above “Production Embodiment 1A.”

[Step (b-1)]

In the Production Embodiment 1a, the step (b-1) is a step of mixing thecarboxy group-containing cellulose fibers obtained through the abovefinely pulverizing step and a quaternary alkylammonium compound, andsubjecting them to an amide-formation reaction with an amine having anaromatic hydrocarbon group, or carrying out only one of the above, toprovide cellulose fibers with which a quaternary alkylammonium cationand/or an aromatic hydrocarbon group is bound. Here, in case where bothof the quaternary alkylammonium cation and the aromatic hydrocarbongroup are introduced, either one may be introduced first, and the orderof introduction is not particular limited.

The quaternary alkylammonium may be introduced by, specifically, mixingthe above carboxy group-containing fine cellulose fibers and aquaternary alkylammonium compound in a solvent.

The quaternary alkylammonium compound usable in the step (b-1) includesthe above ones listed above in the fine cellulose fiber composite a.

The amount of the above quaternary alkylammonium compound used can bedetermined by a desired binding amount in the fine cellulose fibercomposite a. The amount of the quaternary alkylammonium compound used isan amount such that the quaternary alkylammonium cation is used in anamount of preferably 0.1 mol or more, more preferably 0.5 mol or more,even more preferably 0.7 mol or more, and still even more preferably 1mol or more, from the viewpoint of reactivity, and that the quaternaryalkylammonium cation is used in an amount of preferably 50 mol or less,more preferably 20 mol or less, and even more preferably 10 mol or less,from the viewpoint of purity of the manufactured article, based on 1 molof the carboxy groups contained in the carboxy group-containing finecellulose fibers. Here, the quaternary alkylammonium compound may besubject to reaction at one time, or subject to reaction in dividedportions.

As the solvent, it is preferable to select a solvent that dissolves anamine used, and the solvent includes, for example, water, ethanol,isopropanol (IPA), N,N-dimethylformamide (DMF), dimethyl sulfoxide(DMSO), N,N-dimethylacetamide, tetrahydrofuran (THF), a diester obtainedfrom succinic acid and triethylene glycol monomethyl ether, acetone,methyl ethyl ketone (MEK), acetonitrile, dichloromethane, chloroform,toluene, acetic acid, and the like. These solvents can be used alone orin a combination of two or more kinds. Among these polar solvents, adiester obtained from succinic acid and triethylene glycol monomethylether, ethanol, and DMF are preferred.

The temperature during mixing is preferably 0° C. or higher, morepreferably 5° C. or higher, and even more preferably 10° C. or higher,from the viewpoint of reactivity of the amine. In addition, thetemperature is preferably 50° C. or lower, more preferably 40° C. orlower, and even more preferably 30° C. or lower, from the viewpoint ofcoloration of the composite. The mixing time can be appropriately setdepending upon the kinds of the amines and solvents used, and the mixingtime is preferably 0.01 hours or more, more preferably 0.1 hours ormore, and even more preferably 1 hour or more, and preferably 48 hoursor less, more preferably 24 hours or less, and even more preferably 12hours or less, from the viewpoint of reactivity of the amine.

In addition, the aromatic hydrocarbon group is introduced, specifically,by subjecting the above carboxy group-containing fine cellulose fibersto an amide-formation reaction with an amine having an aromatichydrocarbon group.

The amine having an aromatic hydrocarbon group usable in the step (b-1)includes the above ones listed above in the fine cellulose fibercomposite a.

The amount of the above amine having an aromatic hydrocarbon group usedcan be determined by a desired binding amount in the fine cellulosefiber composite a. The amount of the amine used is an amount such thatthe amine groups are used in an amount of preferably 0.1 mol or more,more preferably 0.5 mol or more, even more preferably 0.7 mol or more,and still even more preferably 1 mol or more, from the viewpoint ofreactivity, and preferably 50 mol or less, more preferably 20 mol orless, and even more preferably 10 mol or less, from the viewpoint ofpurity of the manufactured article, based on 1 mol of the carboxy groupscontained in the carboxy group-containing fine cellulose fibers. Here,the amine having an aromatic hydrocarbon group in an amount contained inthe range defined above may be subjected to a reaction at one time, orsubjected to a reaction in divided portions. In a case where the amineis a monoamine, the above amine group and amine are the same.

The reaction of the above carboxy group-containing fine cellulose fiberswith the above amine having an aromatic hydrocarbon group is a“condensation reaction” or “amide bond formation reaction,” which can becarried out in reference to the step (B) in the above “ProductionEmbodiment 1A.”

After the above mixing and after the reaction, post-treatments may beappropriately carried out in order to remove unreacted amines, thecondensing agent, and the like. As the method for post-treatments, forexample, filtration, centrifugation, dialysis, or the like can be used.

Thus, cellulose fibers in which the fine cellulose fibers are bound withthe quaternary alkylammonium cation and/or the aromatic hydrocarbongroup can be obtained.

[Step (b-2)]

In Production Embodiment 1a, the step (b-2) is a step of subjecting thecellulose fibers obtained through the above steps containing aquaternary alkylammonium cation and/or an aromatic hydrocarbon group,and an amine having an EO/PO copolymer moiety or a PO polymer moiety toan amide-formation reaction, to provide a fine cellulose fibercomposite. Specifically, the step can be carried out in reference to thestep (B) in the above “Production Embodiment 1A.”

The amine having an EO/PO copolymer moiety or a PO polymer moiety usablein the step (b-2) includes the above ones listed above in the finecellulose fiber composite a, and the amount used can be determineddepending upon the desired binding amount in the fine cellulose fibercomposite a. The amount of the amine used is an amount such that theamine groups are used in an amount of preferably 0.01 mol or more, morepreferably 0.05 mol or more, even more preferably 0.07 mol or more, andstill even more preferably 0.1 mol or more, from the viewpoint ofreactivity, and preferably 5 mol or less, more preferably 2 mol or less,even more preferably 1 mol or less, and even more preferably 0.5 mol orless, from the viewpoint of purity of the manufactured article, based on1 mol of carboxy group contained in the carboxy group-containing finecellulose fibers. Here, the amine may be subjected to a reaction at onetime, or may be subject to a reaction in divided portions.

After the above reaction, the post-treatments can be carried out in thesame manner as in the above step (b-1).

Production Embodiment 2a can be carried out in the same manner as inProduction Embodiment 1a, except that each of the above steps arecarried out in the order of the step (a), the step (b-1), the step(b-2), and the finely pulverizing step.

The fine cellulose fiber composite a thus obtained can be used in adispersion state after carrying out the above post-treatments, orsolvents are removed from the dispersion by a drying treatment or thelike, to provide a dried fine cellulose fiber composite in a powderform, and this powder can also be used. Here, the “powder form” is apowder form in which the fine cellulose fiber composites are aggregated,and does not mean the cellulose particles.

In addition, the average fiber size of the fine cellulose fibercomposite a is preferably 0.1 nm or more, more preferably 0.2 nm ormore, even more preferably 0.5 nm or more, even more preferably 0.8 nmor more, and still even more preferably 1 nm or more, from the viewpointof heat resistance (lesser extent of coloration upon molding). Inaddition, the average fiber size is preferably 200 nm or less, morepreferably 100 nm or less, even more preferably 50 nm or less, even morepreferably 20 nm or less, and still even more preferably 10 nm or less,from the viewpoint of mechanical strength or the like.

It is preferable that the fine cellulose fiber composite a contained inthe resin composition of the present invention is, as mentioned above,fine cellulose fibers that are connected with an EO/PO copolymer moietyor a PO polymer moiety via an amide bond, and that are ionically bondedto a quaternary alkylammonium cation and/or that are amide-bonded to anaromatic hydrocarbon group, wherein the average fiber size is from 0.1to 200 nm.

[Fine Cellulose Fiber Composite Dispersion]

The fine cellulose fiber composite dispersion of the present inventioncontains a fine cellulose fiber composite in which an EO/PO copolymermoiety or a PO polymer moiety is connected via an amide bond to theabove fine cellulose fibers, and a plasticizer. As the fine cellulosefiber composite, both the fine cellulose fiber composite A and the finecellulose fiber composite a can be used, and they can be used together.

The content of the above fine cellulose fiber composite in thedispersion is preferably 0.01% by mass or more, more preferably 0.03% bymass or more, even more preferably 0.05% by mass or more, and even morepreferably 0.1% by mass or more, from the viewpoint of improvingmechanical strength or the like of the resin composition upon blendingthe dispersion in the resin, and the content is preferably 70% by massor less, more preferably 50% by mass or less, even more preferably 30%by mass or less, even more preferably 10% by mass or less, even morepreferably 5% by mass or less, and even more preferably 3% by mass orless, from the viewpoint of preventing the aggregation of the composite.

In addition, the amount of the above fine cellulose fibers (conversionamount) in the dispersion is preferably 0.01% by mass or more, morepreferably 0.03% by mass or more, even more preferably 0.05% by mass ormore, even more preferably 0.08% by mass or more, and even morepreferably 0.1% by mass or more, from the viewpoint of improvingmechanical strength or the like of the resin composition upon blendingthe dispersion in the resin, and the amount is preferably 30% by mass orless, more preferably 20% by mass or less, even more preferably 10% bymass or less, even more preferably 5% by mass or less, even morepreferably 1% by mass or less, even more preferably 0.5% by mass orless, and still even more preferably 0.3% by mass or less, from theviewpoint of preventing the aggregation of the composite. Here, theamount of the fine cellulose fibers (conversion amount) as used hereincan be obtained in accordance with a method described in Examples setforth below from the fine cellulose fiber composite.

(Plasticizer)

The plasticizer in the dispersion of the present invention is notparticularly limited, and includes conventionally known plasticizerspolycarboxylic acid esters such as phthalic acid esters, succinic acidesters, and adipic acid esters; fatty acid esters of an aliphatic polyolsuch as glycerol; and the like. Among them, an ester compound containingtwo or more ester groups in the molecule, the ester compound in which atleast one kind of the alcohol component constituting the ester compoundis an adduct of an alcohol reacted with an alkylene oxide having from 2to 3 carbon atoms in an amount of from 0.5 to 5 mol on average, per onehydroxyl group, is preferred. Specific examples include plasticizerslisted in Japanese Patent Laid-Open Nos. 2008-174718 and 2008-115372.

The content of the plasticizer in the dispersion is preferably 95% bymass or more, more preferably 97% by mass or more, even more preferably99% by mass or more, and still even more preferably 99.5% by mass ormore, from the viewpoint of improving mechanical strength or the like ofthe resin composition when the dispersion is blended with the resin, andat the same time improving heat resistance, transparency, andmoldability of the molded article when providing the molded article, andthe content is preferably 99.95% by mass or less, more preferably 99.9%by mass or less, and even more preferably 99.8% by mass or less, fromthe viewpoint of including the fine cellulose fiber composite and fromthe viewpoint of preventing the strength of the resin from beinglowered.

Since the fine cellulose fiber composite dispersion of the presentinvention contains smaller amounts of aggregates and has excellenttransparency and heat resistance, the dispersion can be suitably used inthe production of the resin composition, containing a thermoplasticresin or a curable resin mentioned later, and a fine cellulose fibercomposite.

[Resin Composition]

The resin composition of the present invention contains a thermoplasticresin or a curable resin and the above fine cellulose fiber composite.By including the above fine cellulose fiber composite, mechanicalstrength or the like can be improved while maintaining, or withoutsignificantly impairing, transparency of the above resin. As the finecellulose fiber composite as used herein, both of the fine cellulosefiber composite A and the fine cellulose fiber composite a can be used,and they may be used together.

The thermoplastic resin includes saturated polyester-based resins suchas polylactic acid resin; olefinic resins such as polyethylene-basedresins and polypropylene-based resins; cellulose-based resins such astriacetylated cellulose and diacetylated cellulose; nylon resins, vinylchloride resins, styrene resins, (meth)acrylic resins, vinyl etherresins, polyvinyl alcohol resins, polyamide-based resins,polycarbonate-based resins, polysulfonate-based resins and the like.These thermoplastic resins may be used alone or may be used as mixedresins of two or more kinds. Among them, the polyester-based resins andthe (meth)acrylic resins are preferred, from the viewpoint of providinga resin composition having a smaller amount of aggregates, and havingexcellent transparency. Here, the term (meth)acrylic resin as usedherein means to embrace methacrylic resins and acrylic resins.

The polyester-based resin is not particularly limited so long as thepolyester-based resin is known in the art, those having biodegradabilityare preferred, and biodegradable polyester resins are preferred.Specific examples include aliphatic polyester resins such as polyhydroxybutyrate, polycaprolactone, polybutylene succinate, polybutylenesuccinate/adipate, polyethylene succinate, polylactic acid resin,polymalic acid, polyglycolic acid, polydioxanone, and poly(2-oxetanone);aliphatic aromatic co-polyester resins such as polybutylenesuccinate/terephthalate, polybutylene adipate/terephthalate, andpolytetramethylene adipate/terephthalate; mixtures of a natural polymersuch as starch, cellulose, chitin, chitosan, gluten, gelatin, zain,soybean protein, collagen, or keratin, and the aliphatic polyesterresins or the aliphatic aromatic co-polyester resins mentioned above;and the like. Among them, the polybutylene succinate and the polylacticacid resin are preferred, and the polylactic acid resin is morepreferred, from the viewpoint of having excellent workability, economicadvantages, availability, and physical properties. Here, the term“biodegradable or biodegradability” as used herein refers to a propertywhich is capable of being degraded to low molecular compounds bymicroorganisms in nature. Specifically, the term means biodegradabilitybased on “test on aerobic and ultimate biodegradation degree anddisintegration degree under controlled aerobic compost conditions” ofJIS K6953, ISO 14855.

The polylactic acid resin includes commercially available polylacticacid resins, for example, those manufactured by Nature Works LLC underthe trade names of Nature Works PLA/NW3001D, NW4032D, and N4000, andthose manufactured by TOYOTA MOTOR CORPORATION under the trade names ofEcoplastic U'z S-09, S-12, S-17, etc.; and polylactic acid resinssynthesized from lactic acid and lactides. A polylactic acid resinhaving an optical purity of 90% or more is preferred, from the viewpointof improving strength and heat resistance, and, for example, polylacticacid resins such as NW4032D and N4000, manufactured by Nature Works LLChaving relative large molecular weights and high optical purity arepreferred.

As the (meth)acrylic resin, those containing 50% by weight or more ofmethyl (meth)acrylate, on the basis of a total of the monomer units ofthe entire polymer constituting the resin are preferred, and methacrylicresin is more preferred.

The methacrylic resin can be produced by copolymerizing methylmethacrylate and other monomer copolymerizable therewith. Thepolymerization method is not particularly limited, and includes, forexample, a bulk polymerization method, a solution polymerization method,a suspension polymerization method, and an injection mold polymerizationmethod, e.g. a cell casting polymerization method, and the injectionmold polymerization method, e.g. a cell casting polymerization method,is preferred, from the viewpoint of productivity. In addition, themethacrylic resin having excellent heat resistance is obtained bysubjecting a polymerizable mixture containing the above monomer mixtureand a radical polymerization initiator to a polymerization reaction.

The curable resin is preferably a photo-curable resin and/or athermosetting resin.

The photo-curable resin allows to progress the polymerization reactionby active energy ray irradiation of ultraviolet rays or electron beams,using a photopolymerization initiator that generates a radical orcation.

The above photopolymerization initiator includes, for example,acetophenones, benzophenones, ketals, anthraquinones, thioxanthones, azocompounds, peroxides, 2,3-dialkylthione compounds, disulfide compounds,thiuram compounds, fluoroamine compounds, and the like. More specificexamples include 1-hydroxy-cyclohexyl-phenyl-ketone,2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one, benzyl methylketone, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one,1-(4-isopropylphenyl)-2-hydroxy-2-hydroxy-2-methylpropan-1-one,benzophenone, and the like. Among them,1-hydroxy-cyclohexyl-phenyl-ketone is preferred, from the viewpoint ofimproving antistatic property, waterproofness, transparency, and rubbingresistance.

With the photopolymerization initiator, for example, a monomer(monofunctional monomer and/or polyfunctional monomer), or an oligomeror resin or the like having a reactive unsaturated group can bepolymerized.

The monofunctional monomer includes, for example, (meth)acrylic monomerssuch as (meth)acrylic acid esters; vinyl-based monomers such as vinylpyrrolidone; (meth)acrylates having a bridged cyclohydrocarbon groupsuch as isobornyl (meth)acrylate and adamantyl (meth)acrylate; and thelike. The polyfunctional monomer contains a polyfunctional monomerhaving 2 to 8 or so polymerizable groups, and the bifunctional monomerincludes, for example, di(meth)acrylates having a bridgedcyclohydrocarbon group such as ethylene glycol di(meth)acrylate andpropylene glycol di(meth)acrylate, and the like. The tri- toocto-functional monomer includes, for example, glyceroltri(meth)acrylate, and the like.

Examples of the oligomer or resin having a reactive unsaturated groupinclude (meth)acrylates of alkylene oxide adducts of bisphenol A, epoxy(meth)acrylates (bisphenol A type epoxy (meth)acrylate, novolak typeepoxy (meth)acrylate, etc.), polyester (meth)acrylates (e.g., aliphaticpolyester-type (meth)acrylates, aromatic polyester-type (meth)acrylates,etc.), urethane (meth)acrylates (polyester-type urethane(meth)acrylates, polyether-type urethane (meth)acrylates, etc.),silicone (meth)acrylates, and the like. The above oligomer or resin maybe used together with the above monomer.

The photo-curable resin is preferred, from the viewpoint of providing aresin composition having a smaller amount of aggregates, and havingexcellent transparency.

The thermosetting resin includes, for example, epoxy resins; phenolresins; urea resins; melamine resins; unsaturated polyester resins;diallyl phthalate resins; polyurethane resins; silicon-containingresins; polyimide resins; elastomeric resins; and the like. Thethermosetting resin can be used alone or in a combination of two or morekinds. Among them, the epoxy resins are more preferred, from theviewpoint of providing a resin composition having a smaller amount ofaggregates, and having excellent transparency.

When an epoxy resin is used in the above resin component, it ispreferable to use a curing agent. By blending a curing agent, moldingmaterials obtained from the resin composition can be firmly molded,whereby the mechanical strength can be improved. Here, the content ofthe curing agent may be appropriately set depending upon the kinds ofthe curing agents used.

In addition, in the present invention, an elastomeric resin can be usedas a thermosetting resin. As the elastomeric resin, the carbon blackblend product is widely used as a reinforcing material in order toincrease the strength, but the reinforcing effects are considered tohave some limitations. However, in the present invention, it isconsidered as follows. Since the fine cellulose fiber composite of thepresent invention is blended in the elastomeric resin, the finecellulose fiber composites themselves each having the above ethyleneoxide/propylene oxide (EO/PO) copolymer moiety or propylene oxide (PO)polymer moiety increase dispersibility into the resin owing to repulsioncaused by steric repulsion, and at the same time the cellulose fibercomposites themselves increase affinity to the resin, so that thedispersibility in the resin becomes excellent when blended with theresin, and consequently the resulting resin composition has excellentmechanical strength, thereby making it possible to further improve heatresistance and dimensional stability. Accordingly, in the presentinvention, the problem of the elastomeric resin of being disadvantageousin mechanical strength can be overcome by blending the fine cellulosefiber composite of the present invention, thereby making it possible toexhibit excellent effects of having excellent mechanical strength andfurther improved heat resistance and dimensional stability.

The kinds of the elastomeric resin are not particularly limited, anddiene-based rubbers are preferred, from the viewpoint ofreinforceability.

The diene-based rubber includes natural rubber (NR), polyisoprene rubber(IR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber(SBR), butyl rubber (IIR), butadiene-acrylonitrile copolymer rubber(NBR), modified natural rubbers, and the like. The modified naturalrubber includes epoxidized natural rubber, hydrogenated natural rubber,and the like. These can be used alone or in a combination of two or morekinds. Among them, one or more members selected from natural rubber(NR), polyisoprene rubber (IR), polybutadiene rubber (BR), andstyrene-butadiene copolymer rubber (SBR) are preferred, and one or moremembers selected from natural rubber (NR), styrene-butadiene copolymerrubber (SBR), and modified natural rubbers are more preferred, from theviewpoint of satisfying both favorable workability and high-impactresilience of the rubber composition.

As the fine cellulose fiber composite, the fine cellulose fibercomposite of the present invention mentioned above can be used. In otherwords, as the fine cellulose fiber composite, both of the fine cellulosefiber composite A and the fine cellulose fiber composite a can be used.

The content of the resin in the resin composition, the amount of thefine cellulose fiber composite based on the resin, and the amount of thefine cellulose fibers based on the resin (conversion amount) depend onthe kinds of the resins, which are as follows.

The content of the resin in the resin composition of the presentinvention is preferably 50% by mass or more, more preferably 60% by massor more, 70% by mass or more, even more preferably 80% by mass or more,and even more preferably 85% by mass or more, from the viewpoint ofproducing a molded article, and the content is preferably 99% by mass orless, more preferably 98% by mass or less, even more preferably 95% bymass or less, and even more preferably 93% by mass or less, from theviewpoint of including the fine cellulose fiber composite, a plasticizeror the like.

The content of the fine cellulose fiber composite in the resincomposition of the present invention is preferably 0.01% by mass ormore, more preferably 0.05% by mass or more, even more preferably 0.1%by mass or more, even more preferably 0.3% by mass or more, even morepreferably 0.5% by mass or more, even more preferably 1% by mass ormore, even more preferably 2% by mass or more, and still even morepreferably 3% by mass or more, from the viewpoint of mechanicalstrength, dimensional stability, and heat resistance of the resincomposition obtained, and the content is preferably 50% by mass or less,more preferably 40% by mass or less, even more preferably 30% by mass orless, even more preferably 20% by mass or less, and still even morepreferably 15% by mass or less, from the viewpoint of transparency ofthe resin composition obtained.

The amount of the fine cellulose fiber composite in the resincomposition of the present invention, based on 100 parts by mass of theresin, is preferably 0.01 parts by mass or more, more preferably 0.05parts by mass or more, even more preferably 0.1 parts by mass or more,even more preferably 0.3 parts by mass or more, even more preferably 0.5parts by mass or more, even more preferably 1 part by mass or more, andstill even more preferably 3 parts by mass or more, from the viewpointof mechanical strength, dimensional stability, and heat resistance ofthe resin composition obtained, and the amount is preferably 60 parts bymass or less, more preferably 50 parts by mass or less, even morepreferably 40 parts by mass or less, even more preferably 30 parts bymass or less, even more preferably 20 parts by mass or less, and evenmore preferably 15 parts by mass or less, from the viewpoint oftransparency of the resin composition obtained.

The amount of the fine cellulose fibers (conversion amount) in the resincomposition of the present invention, based on 100 parts by mass of theresin, is preferably 0.01 parts by mass or more, more preferably 0.05parts by mass or more, and even more preferably 0.08 parts by mass ormore, from the viewpoint of mechanical strength, dimensional stability,and heat resistance of the resin composition obtained, and the amount ispreferably 60 parts by mass or less, more preferably 50 parts by mass orless, even more preferably 40 parts by mass or less, even morepreferably 30 parts by mass or less, even more preferably 20 parts bymass or less, even more preferably 15 parts by mass or less, and evenmore preferably 10 parts by mass or less, from the viewpoint oftransparency of the resin composition obtained.

The preferred ranges according to the kinds of the resins are listedhereinbelow.

(1) Case where Resin is Thermoplastic Resin

The content of the resin in the resin composition of the presentinvention is not particularly limited, and the content is preferably 50%by mass or more, more preferably 60% by mass or more, even morepreferably 70% by mass or more, even more preferably 80% by mass ormore, and even more preferably 85% by mass or more, from the viewpointof producing a molded article. The content is preferably 99% by mass orless, more preferably 98% by mass or less, even more preferably 95% bymass or less, even more preferably 93% by mass or less, even morepreferably 90% by mass or less, and even more preferably 87% by mass orless, from the viewpoint of including a fine cellulose fiber composite,a plasticizer and the like.

The amount of the fine cellulose fiber composite in the resincomposition of the present invention, based on 100 parts by mass of theresin, is preferably 0.01 parts by mass or more, more preferably 0.05parts by mass or more, even more preferably 0.1 parts by mass or more,even more preferably 0.5 parts by mass or more, even more preferably 1part by mass or more, even more preferably 3 parts by mass or more, evenmore preferably 6 parts by mass or more, and even more preferably 10parts by mass or more, from the viewpoint of mechanical strength,dimensional stability, and heat resistance of the resin compositionobtained. The amount is preferably 100 parts by mass or less, morepreferably 70 parts by mass or less, even more preferably 50 parts bymass or less, even more preferably 40 parts by mass or less, even morepreferably 30 parts by mass or less, even more preferably 20 parts bymass or less, even more preferably 15 parts by mass or less, even morepreferably 5 parts by mass or less, even more preferably 3 parts by massor less, even more preferably 1 part by mass or less, even morepreferably 0.5 parts by mass or less, and still even more preferably 0.3parts by mass or less, from the viewpoint of transparency of the resincomposition obtained.

The amount of the fine cellulose fibers (conversion amount) in the resincomposition of the present invention, based on 100 parts by mass of theresin, is preferably 0.01 parts by mass or more, more preferably 0.05parts by mass or more, even more preferably 0.08 parts by mass or more,even more preferably 0.1 parts by mass or more, even more preferably 0.3parts by mass or more, even more preferably 0.5 parts by mass or more,even more preferably 2 parts by mass or more, and even more preferably 5parts by mass or more, from the viewpoint of mechanical strength,dimensional stability, and heat resistance of the resin compositionobtained. The amount is preferably 60 parts by mass or less, morepreferably 50 parts by mass or less, even more preferably 40 parts bymass or less, even more preferably 35 parts by mass or less, even morepreferably 30 parts by mass or less, even more preferably 20 parts bymass or less, even more preferably 15 parts by mass or less, even morepreferably 10 parts by mass or less, even more preferably 5 parts bymass or less, even more preferably 3 parts by mass or less, even morepreferably 1 part by mass or less, even more preferably 0.5 parts bymass or less, and still even more preferably 0.3 parts by mass or less,from the viewpoint of transparency of the resin composition obtained.

(2) Case where Resin is Photo-Curable Resin

The content of the resin in the resin composition of the presentinvention is not particularly limited, and the content is preferably 50%by mass or more, more preferably 60% by mass or more, even morepreferably 70% by mass or more, even more preferably 80% by mass ormore, and even more preferably 85% by mass or more, from the viewpointof producing a molded article. The content is preferably 99% by mass orless, more preferably 98% by mass or less, even more preferably 96% bymass or less, and even more preferably 93% by mass or less, from theviewpoint of including a fine cellulose fiber composite, and the like.

The amount of the fine cellulose fiber composite in the resincomposition of the present invention, based on 100 parts by mass of theresin, is preferably 0.01 parts by mass or more, more preferably 0.05parts by mass or more, even more preferably 0.1 parts by mass or more,even more preferably 0.5 parts by mass or more, even more preferably 1part by mass or more, even more preferably 3 parts by mass or more, evenmore preferably 6 parts by mass or more, and still even more preferably10 parts by mass or more, from the viewpoint of mechanical strength,dimensional stability, and heat resistance of the resin compositionobtained. In addition, the amount is preferably 100 parts by mass orless, more preferably 70 parts by mass or less, even more preferably 50parts by mass or less, even more preferably 40 parts by mass or less,even more preferably 30 parts by mass or less, even more preferably 20parts by mass or less, even more preferably 15 parts by mass or less,and even more preferably 10 parts by mass or less, from the viewpoint oftransparency of the resin composition obtained.

The amount of the fine cellulose fibers (conversion amount) in the resincomposition of the present invention, based on 100 parts by mass of theresin, is preferably 0.01 parts by mass or more, more preferably 0.05parts by mass or more, even more preferably 0.1 parts by mass or more,even more preferably 0.5 parts by mass or more, even more preferably 0.8parts by mass or more, even more preferably 1 part by mass or more, evenmore preferably 3 parts by mass or more, and still even more preferably5 parts by mass or more, from the viewpoint of mechanical strength,dimensional stability, and heat resistance of the resin compositionobtained. In addition, the amount is preferably 50 parts by mass orless, more preferably 40 parts by mass or less, even more preferably 35parts by mass or less, even more preferably 30 parts by mass or less,even more preferably 20 parts by mass or less, even more preferably 15parts by mass or less, and even more preferably 10 parts by mass orless, from the viewpoint of transparency of the resin compositionobtained.

(3) Case where Resin is Thermosetting Resin

The content of the resin in the resin composition of the presentinvention is not particularly limited, and the content is preferably 50%by mass or more, more preferably 60% by mass or more, even morepreferably 70% by mass or more, even more preferably 80% by mass ormore, and even more preferably 85% by mass or more, from the viewpointof producing a molded article. The content is preferably 99% by mass orless, more preferably 98% by mass or less, even more preferably 96% bymass or less, even more preferably 90% by mass or less, even morepreferably 85% by mass or less, and even more preferably 80% by mass orless, from the viewpoint of including a fine cellulose fiber composite,and the like.

The amount of the fine cellulose fiber composite in the resincomposition of the present invention, based on 100 parts by mass of theresin, is preferably 0.01 parts by mass or more, more preferably 0.05parts by mass or more, even more preferably 0.1 parts by mass or more,even more preferably 0.5 parts by mass or more, even more preferably 1part by mass or more, even more preferably 3 parts by mass or more, evenmore preferably 7 parts by mass or more, even more preferably 10 partsby mass or more, and even more preferably 15 parts by mass or more, fromthe viewpoint of mechanical strength, dimensional stability, and heatresistance of the resin composition obtained. In addition, the amount ispreferably 100 parts by mass or less, more preferably 70 parts by massor less, even more preferably 50 parts by mass or less, even morepreferably 40 parts by mass or less, even more preferably 30 parts bymass or less, even more preferably 20 parts by mass or less, even morepreferably 15 parts by mass or less, and even more preferably 10 partsby mass or less, from the viewpoint of transparency of the resincomposition obtained.

The amount of the fine cellulose fibers (conversion amount) in the resincomposition of the present invention, based on 100 parts by mass of theresin, is preferably 0.01 parts by mass or more, more preferably 0.05parts by mass or more, even more preferably 0.08 parts by mass or more,even more preferably 0.1 parts by mass or more, even more preferably 0.5parts by mass or more, even more preferably 0.8 parts by mass or more,even more preferably 1 part by mass or more, even more preferably 3parts by mass or more, even more preferably 5 parts by mass or more, andeven more preferably 8 parts by mass or more, from the viewpoint ofmechanical strength, dimensional stability, and heat resistance of theresin composition obtained. In addition, the amount is preferably 50parts by mass or less, more preferably 40 parts by mass or less, evenmore preferably 35 parts by mass or less, even more preferably 30 partsby mass or less, even more preferably 20 parts by mass or less, evenmore preferably 15 parts by mass or less, even more preferably 10 partsby mass or less, even more preferably 5 parts by mass or less, and evenmore preferably 3 parts by mass or less, from the viewpoint oftransparency of the resin composition obtained.

The resin composition of the present invention can contain a plasticizerin addition to the above components. As the plasticizer, theplasticizers that are contained in the fine cellulose fiber compositedispersion of the present invention mentioned above can be used in thesame manner.

The content of the plasticizer, based on 100 parts by mass of the resin,is preferably 1 part by mass or more, more preferably 3 parts by mass ormore, and even more preferably 5 parts by mass or more, from theviewpoint of improving transparency of the molded article when formedinto a molded article, and the content is preferably 30 parts by mass orless, more preferably 20 parts by mass or less, and even more preferably15 parts by mass or less, from the same viewpoint.

The resin composition of the present invention can contain, as othercomponents besides those mentioned above, a crystal nucleating agent, afiller including an inorganic filler and an organic filler, a hydrolysisinhibitor, a flame retardant, an antioxidant, a lubricant such as ahydrocarbon wax or an anionic surfactant, an ultraviolet absorbent, anantistatic agent, an anti-clouding agent, a photostabilizer, a pigment,a mildewproof agent, a bactericidal agent, a blowing agent, or asurfactant; a polysaccharide such as starch or alginic acid; a naturalprotein such as gelatin, glue, or casein; an inorganic compound such astannin, zeolite, ceramics, or metal powder; a perfume; a fluiditymodulator; a leveling agent; electroconductive agent; a ultravioletdispersant; a deodorant; or the like, within the range that would notimpair the effects of the present invention. In addition, similarly,other polymeric materials and other resin compositions may be properlyadded within the range that would not impair the effects of the presentinvention. As to the content proportion of the optional additives, theoptional additives may be properly contained within the range that wouldnot impair the effects of the present invention, and the contentproportion of the optional additives is, for example, preferably 10% bymass or so or less, and more preferably 5% by mass or so or less, of theresin composition.

In addition, when the resin composition of the present inventioncontains a rubber-based resin, the resin composition can be optionallyblended, in addition to those mentioned above, with various additivesgenerally blended in tires and other rubbers as other components besidesthose mentioned above, such as fillers for reinforcements such as carbonblack or silica ordinarily used in the rubber industries; variouschemicals including, for example, a vulcanizing agent, a vulcanizationaccelerator, an aging inhibitor, a scorching inhibitor, zinc flower,stearic acid, a process oil, a vegetable fat or oil, a plasticizer orthe like in a conventional general amount within the range that wouldnot impair the object of the present invention.

The resin composition of the present invention can be prepared withoutparticular limitations, so long as the resin composition contains athermoplastic resin or a curable resin, and a fine cellulose fibercomposite. For example, raw materials containing a thermoplastic resinor a curable resin, and a fine cellulose fiber composite, and furtheroptionally various additives may be stirred with a Henschel mixer, ormelt-kneaded with a known kneader such as a tightly closed kneader, asingle-screw or twin-screw extruder, or an open roller-type kneader. Ina case where a solvent is contained, the resin composition can beprepared by a solvent casting method.

Since the resin composition of the present invention has favorableworkability, and excellent heat resistance, the resin composition can besuitably used in various applications such as daily sundries, householdelectric appliance parts, and automobile parts, and especially inautomobile applications.

[Resin Molded Article]

The resin molded article can be prepared by subjecting the above resincomposition to molding, such as extrusion-molding, injection-molding, orpress molding. A preferred embodiment will be described hereinbelow fora case of a thermoplastic resin.

In extrusion molding, a resin composition of the present invention whichis filled in a heated extruder is melted, and thereafter extruded from aT die, whereby a sheet-like molded product can be obtained. Thissheet-like molded product is immediately brought into contact with acooling roller to cool the sheet to a temperature equal to or lower thanthe Tg of the resin composition, thereby adjusting the crystallineproperty of the sheet, and subsequently the sheets are detached from thecooling roller, and wound around with a winding roller, whereby asheet-like molded article can be obtained. Here, when filled in theextruder, the raw materials constituting the resin composition of thepresent invention, for example, raw materials containing a resin and afine cellulose fiber composite, and further optionally various additivesmay be filled, melt-kneaded, and thereafter subjected toextrusion-molding.

The temperature of the extruder is preferably 170° C. or higher, morepreferably 175° C. or higher, and even more preferably 180° C. orhigher, from the viewpoint of homogeneously mixing a resin compositionand preventing the deterioration of the resin. In addition, thetemperature is preferably 240° C. or lower, more preferably 220° C. orlower, and even more preferably 210° C. or lower. Also, the temperatureof the cooling roller is preferably 40° C. or lower, more preferably 30°C. or lower, and even more preferably 10° C. or lower, from theviewpoint of adjusting the crystalline property of the molded article.

In addition, the extrusion rate is preferably 1 m/minute or more, morepreferably 5 m/minute or more, and even more preferably 10 m/minute ormore, from the viewpoint of adjusting the crystalline property of themolded article. In addition, the extrusion rate is preferably 200m/minute or less, 150 m/minute or less, and even more preferably 100m/minute or less.

In the injection-molding, for example, the resin composition of thepresent invention is filled in a mold having a desired shape using aninjection-molding machine with a cylinder temperature set at preferablyfrom 180° to 220° C., and more preferably from 180° to 210° C., wherebythe resin composition can be molded.

The mold temperature is preferably 110° C. or lower, more preferably 90°C. or lower, and even more preferably 80° C. or lower, from theviewpoint of improving crystallization velocity and improvingoperability. In addition, the mold temperature is preferably 30° C. orhigher, more preferably 40° C. or higher, and even more preferably 60°C. or higher.

The holding time inside the mold is not particularly limited, and theholding time is preferably from 2 to 60 seconds, more preferably from 3to 30 seconds, and even more preferably from 5 to 20 seconds, forexample, in a mold at 90° C., from the viewpoint of productivity of themolded article made of the resin composition.

When a sheet-like molded article, for example, is molded by pressmolding, a molded article can be prepared by subjecting a resincomposition of the present invention to put and press into a framehaving a sheet-like shape.

As the temperature and pressure of the press molding, it is preferablethat the press can be carried out, for example, preferably under theconditions of a temperature of from 170° to 240° C. and a pressure offrom 5 to 30 MPa, more preferably under the conditions of a temperatureof from 175° to 220° C. and a pressure of from 10 to 25 MPa, and evenmore preferably under the conditions of a temperature of from 180° to210° C. and a pressure of from 10 to 20 MPa. The press time cannot beunconditionally determined because the press time depends upon thetemperature and pressure of the press, and the press time is preferablyfrom 1 to 10 minutes, more preferably from 1 to 7 minutes, and even morepreferably from 1 to 5 minutes.

In addition, immediately after the press under the above conditions, itis preferable that the resin composition is cooled by subjecting topress preferably under the conditions of a temperature of from 0° to100° C. and a pressure of from 0.1 to 30 MPa, more preferably under theconditions of a temperature of from 10° to 100° C. and a pressure offrom 0.1 to 10 MPa, and even more preferably under the conditions of atemperature of from 10° to 90° C. and a pressure of from 0.1 to 5 MPa.By pressing under the above temperature conditions, a resin compositionof the present invention is cooled to a temperature of equal to or lowerthan its Tg, thereby adjusting its crystalline property. Therefore, thepress time cannot be unconditionally determined because the press timedepends upon the press temperature and pressure, and the press time ispreferably from 1 to 10 minutes, more preferably from 1 to 7 minutes,and even more preferably from 1 to 5 minutes.

When a sheet-like molded article is prepared, its thickness ispreferably 0.05 mm or more, more preferably 0.1 mm or more, and evenmore preferably 0.15 mm or more, from the viewpoint of workability. Inaddition, the thickness is 1.5 mm or less, more preferably 1.0 mm orless, and even more preferably 0.5 mm or less.

The molded article of the resin composition of the present inventionthus obtained has excellent mechanical strength and heat resistance, sothat the molded article can be suitably used in various applicationslisted in the above resin composition.

With respect to the above-mentioned embodiments, the present inventionfurther discloses the following fine cellulose fiber composite, and theresin composition or molded article containing the composite.

<1> A fine cellulose fiber composite containing fine cellulose fibersand a polymer having an ethylene oxide/propylene oxide (EO/PO) copolymermoiety or a propylene oxide (PO) polymer moiety, the fine cellulosefibers being connected with the polymer via an amide bond (also referredto as a fine cellulose fiber composite A).

<2> The fine cellulose fiber composite according to the above <1>,wherein the average fiber size of the fine cellulose fibers ispreferably 0.1 nm or more, more preferably 0.2 nm or more, even morepreferably 0.5 nm or more, even more preferably 0.8 nm or more, andstill even more preferably 1 nm or more, and preferably 200 nm or less,more preferably 100 nm or less, even more preferably 50 nm or less, evenmore preferably 20 nm or less, even more preferably 10 nm or less, andstill even more preferably 5 nm or less.

<3> The fine cellulose fiber composite according to the above <1> or<2>, wherein the carboxy group content of the fine cellulose fibers ispreferably 0.1 mmol/g or more, more preferably 0.4 mmol/g or more, morepreferably 0.6 mmol/g or more, and even more preferably 0.8 mmol/g ormore, and preferably 3 mmol/g or less, more preferably 2 mmol/g or less,even more preferably 1.8 mmol/g or less, and even more preferably 1.5mmol/g or less.<4> The fine cellulose fiber composite according to any one of the above<1> to <3>, wherein the average aspect ratio (fiber length/fiber size)of the fine cellulose fibers is preferably 10 or more, more preferably20 or more, even more preferably 50 or more, and still even morepreferably 100 or more, and preferably 1,000 or less, more preferably500 or less, even more preferably 400 or less, and still even morepreferably 350 or less.<5> The fine cellulose fiber composite according to any one of the above<1> to <4>, wherein the crystallinity of the fine cellulose fibers ispreferably 30% or more, more preferably 35% or more, even morepreferably 40% or more, and still even more preferably 45% or more, andpreferably 95% or less, more preferably 90% or less, even morepreferably 85% or less, and still even more preferably 80% or less.<6> The fine cellulose fiber composite according to any one of the above<1> to <5>, wherein the amine having an EO/PO copolymer moiety or a POpolymer moiety may be preferably any one of a primary amine and asecondary amine, and more preferably a primary amine.<7> The fine cellulose fiber composite according to any one of the above<1> to <6>, wherein the molecular weight of the EO/PO copolymer moietyor the PO polymer moiety is preferably 500 or more, more preferably 700or more, even more preferably 1,000 or more, and even more preferably1,500 or more, and preferably 10,000 or less, more preferably 7,000 orless, even more preferably 5,000 or less, even more preferably 4,000 orless, even more preferably 3,500 or less, and still even more preferably2,500 or less.<8> The fine cellulose fiber composite according to any one of the above<1> to <7>, wherein the PO content ratio (% by mol) in the EO/POcopolymer moiety is preferably 1% by mol or more, more preferably 6% bymol or more, and even more preferably 8% by mol or more, and preferablyless than 100% by mol, more preferably 99% by mol or less, even morepreferably 90% by mol or less, even more preferably 80% by mol or less,even more preferably 74% by mol or less, even more preferably 60% by molor less, even more preferably 51% by mol or less, even more preferably40% by mol or less, and even more preferably 30% by mol or less.<9> The fine cellulose fiber composite according to any one of the above<1> to <8>, wherein the EO/PO copolymer moiety or the PO polymer moietyand the amine are preferably bound directly or via a linking group,wherein the linking group is preferably a hydrocarbon group, and morepreferably an alkylene group having the number of carbon atoms ofpreferably from 1 to 6, and more preferably from 1 to 3.<10> The fine cellulose fiber composite according to any one of theabove <1> to <9>, wherein the amine having an EO/PO copolymer moiety ora PO polymer moiety is preferably a compound represented by thefollowing formula (i):

wherein R₁ is a hydrogen atom, a linear or branched alkyl group havingfrom 1 to 6 carbon atoms, a —CH₂CH(CH₃)NH₂ group, or a group representedby the following formula (ii); EO and PO are present in a random orblock form; a is 0 or a positive number showing an average number ofmoles of EO added; and b is a positive number showing an average numberof moles of PO added, wherein a is preferably exceeding 0, morepreferably 1 or more, even more preferably 5 or more, even morepreferably 10 or more, even more preferably 15 or more, even morepreferably 20 or more, and even more preferably 25 or more, andpreferably 100 or less, more preferably 80 or less, even more preferably60 or less, and even more preferably 45 or less, and wherein b ispreferably 9 or more, more preferably 12 or more, even more preferably17 or more, and still even more preferably 26 or more, and preferably175 or less, more preferably 120 or less, even more preferably 80 orless, even more preferably 70 or less, even more preferably 60 or less,and still even more preferably 44 or less,

wherein the formula (ii) is:

wherein n is 0 or 1; R₂ is a phenyl group, a hydrogen atom, or a linearor branched alkyl group having from 1 to 3 carbon atoms; EO and PO arepresent in a random or block form; c and e show an average number ofmoles of EO added, which is independently a number of from 0 to 50; andd and f show an average number of moles of PO added, which isindependently a number of from 1 to 50.

<11> The fine cellulose fiber composite according to any one of theabove <1> to <10>, wherein the binding amount of the amide groups havingan EO/PO copolymer moiety or a PO polymer moiety in the fine cellulosefiber composite A is preferably 0.01 mmol/g or more, more preferably0.05 mmol/g or more, even more preferably 0.1 mmol/g or more, and evenmore preferably 0.2 mmol/g or more, and preferably 3 mmol/g or less,more preferably 2 mmol/g or less, even more preferably 1 mmol/g or less,and even more preferably 0.5 mmol/g or less.<12> The fine cellulose fiber composite according to any one of theabove <1> to <11>, wherein the modification ratio of the amine having anEO/PO copolymer moiety or a PO polymer moiety in the fine cellulosefiber composite A is preferably 1% or more, more preferably 5% or more,even more preferably 10% or more, even more preferably 15% or more, andeven more preferably 20% or more, and preferably 90% or less, morepreferably 70% or less, even more preferably 50% or less, and even morepreferably 40% or less.<13> The fine cellulose fiber composite according to any one of theabove <1> to <12>, wherein the fine cellulose fiber composite isobtainable by a production method including the following step (A) andstep (B): step (A): oxidizing natural cellulose fibers in the presenceof an N-oxyl compound, to provide carboxy group-containing cellulosefibers; and step (B): subjecting the carboxy group-containing cellulosefibers obtained in the step (A) and an amine having an EO/PO copolymermoiety or a PO polymer moiety to an amide-formation reaction.<14> The fine cellulose fiber composite according to the above <13>,wherein in the step (A), the carboxy group-containing cellulose fibersobtained by the oxidation reaction are subjected to purification, toprovide carboxy group-containing cellulose fibers having high purity.<15> The fine cellulose fiber composite according to the above <14>,wherein the method includes, subsequent to the purification step, finelypulverizing the carboxy group-containing cellulose fibers obtained inthe step (A).<16> The fine cellulose fiber composite according to any one of theabove <13> to <15>, wherein the amount of the amine having an EO/POcopolymer moiety or a PO polymer moiety used is an amount such that theamine groups are used in an amount of preferably 0.1 mol or more, morepreferably 0.5 mol or more, even more preferably 0.7 mol or more, andstill even more preferably 1 mol or more, and preferably 50 mol or less,more preferably 20 mol or less, and even more preferably 10 mol or less,based on one mol of the carboxy groups contained in the carboxygroup-containing fine cellulose fibers.<17> The fine cellulose fiber composite according to any one of theabove <13> to <16>, wherein the reaction temperature is preferably 0° C.or higher, more preferably 5° C. or higher, and even more preferably 10°C. or higher, and preferably 200° C. or lower, more preferably 80° C. orlower, and even more preferably 30° C. or lower, and wherein thereaction time is preferably from 1 to 24 hours, and more preferably from10 to 20 hours.<18> The fine cellulose fiber composite according to any one of theabove <1> to <17>, wherein the average fiber size of the fine cellulosefiber composite A is preferably 0.1 nm or more, more preferably 0.2 nmor more, even more preferably 0.5 nm or more, even more preferably 0.8nm or more, and still even more preferably 1 nm or more, and preferably200 nm or less, more preferably 100 nm or less, even more preferably 50nm or less, even more preferably 20 nm or less, and still even morepreferably 10 nm or less.<19> The fine cellulose fiber composite according to any one of theabove <1> to <18>, wherein the fine cellulose fiber composite A containsfine cellulose fibers and an EO/PO copolymer moiety or a PO polymermoiety, the fine cellulose fiber being connected with the copolymermoiety or polymer moiety via an amide bond, and preferably has anaverage fiber size of from 0.1 to 200 nm.<20> A fine cellulose fiber composite, as one embodiment of a finecellulose fiber composite A, containing fine cellulose fibers and apolymer having an ethylene oxide/propylene oxide (EO/PO) copolymermoiety or a propylene oxide (PO) polymer moiety, wherein the finecellulose fibers are connected with the polymer via an amide bond, andwherein one or two bindings selected from the group consisting of thefollowing (1) and (2) are further introduced (also referred to as a finecellulose fiber composite a):(1) the binding via an ionic bond of a quaternary alkylammonium cationhaving a total number of carbon atoms of from 4 to 40; and(2) the binding via an amide bond of an aromatic hydrocarbon grouphaving a total number of carbon atoms of from 6 to 20.<21> The fine cellulose fiber composite according to the above <20>,wherein the amine having an EO/PO copolymer moiety or a PO polymermoiety is used in the binding of the EO/PO copolymer moiety or the POpolymer moiety, the quaternary alkylammonium compound having a totalnumber of carbon atoms of from 4 to 40 is used in the binding of thequaternary alkylammonium cation having a total number of carbon atoms offrom 4 to 40, and/or an amine having an aromatic hydrocarbon grouphaving a total number of carbon atoms of from 6 to 20 is used in thebinding of an aromatic hydrocarbon group having a total number of carbonatoms of from 6 to 20 (the amine having an EO/PO copolymer moiety or aPO polymer moiety is also referred to as a first amine, and thequaternary alkylammonium compound having a total number of carbon atomsof from 4 to 40 and the amine having an aromatic hydrocarbon grouphaving a total number of carbon atoms of from 6 to 20 is also referredto as a second amine).<22> The fine cellulose fiber composite according to the above <20> or<21>, wherein the fine cellulose fibers are those as defined in any oneof the above <2> to <5>.<23> The fine cellulose fiber composite according to any one of theabove <20> to <22>, wherein the amine having an EO/PO copolymer moietyor a PO polymer moiety is one as defined in any one of the above <6> to<10>.<24> The fine cellulose fiber composite according to any one of theabove <20> to <23>, wherein the quaternary alkylammonium compound havinga total number of carbon atoms of from 4 to 40 preferably contains alkylgroups having from 1 to 20 carbon atoms, wherein the alkyl group may besubstituted or unsubstituted, and more preferably contains one or moremembers selected from the group consisting of a methyl group, an ethylgroup, a propyl group, a butyl group, a lauryl group, a cetyl group, astearyl group, a benzyl group, and a phenethyl group.<25> The fine cellulose fiber composite according to any one of theabove <20> to <24>, wherein in the quaternary alkylammonium compoundhaving a total number of carbon atoms of from 4 to 40, the total numberof carbon atoms is preferably 8 or more, and more preferably 12 or more,and preferably 36 or less, more preferably 32 or less, even morepreferably 24 or less, even more preferably 20 or less, and even morepreferably 18 or less.<26> The fine cellulose fiber composite according to any one of theabove <20> to <25>, wherein the amine having an aromatic hydrocarbongroup may be any of primary amines and secondary amines, and preferablythe primary amines, and the number of the aromatic hydrocarbon groups inthe amine may be one or two, and preferably one.<27> The fine cellulose fiber composite according to any one of theabove <20> to <26>, wherein the number of carbon atoms of the aminehaving an aromatic hydrocarbon group is preferably 18 or less, and morepreferably 12 or less.<28> The fine cellulose fiber composite according to any one of theabove <20> to <27>, wherein the amine having an aromatic hydrocarbongroup is preferably an amine having an aryl group and an amine having anaralkyl group, and more preferably the amine having an aryl group.<29> The fine cellulose fiber composite according to any one of theabove <20> to <28>, wherein in a case where the aromatic hydrocarbongroup in the amine having an aromatic hydrocarbon group is an arylgroup, a total number of carbon atoms is 6 or more, and 20 or less,preferably 14 or less, and more preferably 10 or less, and in a casewhere the aromatic hydrocarbon group is an aralkyl group, a total numberof carbon atoms is 7 or more, and 20 or less, preferably 13 or less,more preferably 11 or less, and even more preferably 9 or less.<30> The fine cellulose fiber composite according to any one of theabove <20> to <29>, wherein in the fine cellulose fiber composite a, inaddition to the amine having an EO/PO copolymer moiety or a PO polymermoiety, either one of a quaternary alkylammonium compound having a totalnumber of carbon atoms of from 4 to 40 or an amine having an aromatichydrocarbon group having a total number of carbon atoms of from 6 to 20may be bound, or each may be bound alone, or may be bound together.<31> The fine cellulose fiber composite according to any one of theabove <20> to <30>, wherein the binding amount of the amine having anEO/PO copolymer moiety or a PO polymer moiety, which is a first amine,in the fine cellulose fiber composite a, is preferably 0.01 mmol/g ormore, more preferably 0.03 mmol/g or more, and even more preferably 0.05mmol/g or more, and preferably 1 mmol/g or less, more preferably 0.5mmol/g or less, even more preferably 0.25 mmol/g or less, even morepreferably 0.1 mmol/g or less, even more preferably 0.08 mmol/g or less,and even more preferably 0.06 mmol/g or less.<32> The fine cellulose fiber composite according to any one of theabove <20> to <31>, wherein the binding amount of the second amine inthe fine cellulose fiber composite a is preferably 0.2 mmol/g or more,more preferably 0.3 mmol/g or more, even more preferably 0.5 mmol/g ormore, even more preferably 0.8 mmol/g or more, and even more preferably1.0 mmol/g or more, and preferably 1.5 mmol/g or less, more preferably1.3 mmol/g or less, and even more preferably 1.2 mmol/g or less.<33> The fine cellulose fiber composite according to any one of theabove <20> to <32>, wherein a total of the binding amount of the firstamine and the binding amount of the second amine in the fine cellulosefiber composite a is preferably 0.2 mmol/g or more, more preferably 0.3mmol/g or more, even more preferably 0.5 mmol/g or more, even morepreferably 0.8 mmol/g or more, and even more preferably 1.0 mmol/g ormore, and preferably 1.5 mmol/g or less, more preferably 1.3 mmol/g orless, and even more preferably 1.2 mmol/g or less.<34> The fine cellulose fiber composite according to any one of theabove <20> to <33>, wherein the modification ratio of the EO/POcopolymer moiety or the PO polymer moiety in the fine cellulose fibercomposite a is preferably 0.5% or more, more preferably 1% or more, evenmore preferably 2% or more, and even more preferably 5% or more, andpreferably 90% or less, more preferably 50% or less, even morepreferably 20% or less, and even more preferably 10% or less.<35> The fine cellulose fiber composite according to any one of theabove <20> to <34>, wherein the modification ratio of the quaternaryalkylammonium cation and/or the aromatic hydrocarbon group in the finecellulose fiber composite a is preferably 10% or more, more preferably20% or more, even more preferably 30% or more, even more preferably 40%or more, even more preferably 50% or more, even more preferably 60% ormore, and even more preferably 70% or more, and preferably 90% or less,more preferably 85% or less, and even more preferably 80% or less.<36> The fine cellulose fiber composite according to any one of theabove <20> to <35>, wherein a total of the modification ratio of thefirst amine and the modification ratio of the second amine in the finecellulose fiber composite a is preferably 10% or more, more preferably20% or more, even more preferably 30% or more, even more preferably 40%or more, even more preferably 50% or more, even more preferably 60% ormore, even more preferably 70% or more, even more preferably 75% ormore, and even more preferably 80% or more, and preferably 100% or less,more preferably 98% or less, even more preferably 95% or less, even morepreferably 90% or less, and even more preferably 85% or less.<37> The fine cellulose fiber composite according to any one of theabove <20> to <36>, wherein in the fine cellulose fiber composite a, amolar ratio of the binding amount of the first amine to the bindingamount of the second amine (first amine/second amine) is preferably 0.01or more, and more preferably 0.03 or more, and preferably 0.4 or less,more preferably 0.3 or less, even more preferably 0.2 or less, even morepreferably 0.1 or less, and even more preferably 0.05 or less.<38> The fine cellulose fiber composite according to any one of theabove <20> to <37>, wherein when the quaternary alkylammonium compoundand the amine having an aromatic hydrocarbon group are used together asthe second amines, a molar ratio of the binding amounts thereof(quaternary alkylammonium compound/amine having aromatic hydrocarbongroup) is preferably 0.1 or more, more preferably 0.2 or more, and evenmore preferably 0.4 or more, and preferably 0.9 or less, more preferably0.8 or less, and even more preferably 0.6 or less.<39> The fine cellulose fiber composite according to any one of theabove <20> to <38>, wherein the order of introduction of the quaternaryalkylammonium compound and the amine having an aromatic hydrocarbongroup into the fine cellulose fibers or the introduction of amine havingan EO/PO copolymer moiety or a PO polymer moiety is such that either onemay be carried out first, and the introduction of the quaternaryalkylammonium compound and the amine having an aromatic hydrocarbongroup is preferably carried out first.<40> The fine cellulose fiber composite according to any one of theabove <20> to <39>, wherein the fine cellulose fiber composite a isobtained by a production method including the following steps (a),(b-1), and (b-2):step (a): oxidizing natural cellulose fibers in the presence of anN-oxyl compound, to provide carboxy group-containing cellulose fibers;andstep (b-1): mixing the carboxy group-containing cellulose fibersobtained in the step (a) and a quaternary alkylammonium compound, andsubjecting them to an amide-formation reaction with an amine having anaromatic hydrocarbon group, or carrying out only one of the above, toprovide cellulose fibers to which the quaternary alkylammonium cationand/or the aromatic hydrocarbon group is bound; andstep (b-2): subjecting the cellulose fibers obtained in the step (b-1)and an amine having an EO/PO copolymer moiety or a PO polymer moiety toan amide-formation reaction.<41> The fine cellulose fiber composite according to the above <40>,wherein, in the step (a), the carboxy group-containing cellulose fibersobtained in the oxidation reaction are subjected to purification, toprovide carboxy group-containing cellulose fibers having high purity.<42> The fine cellulose fiber composite according to the above <41>,wherein, subsequent to the purifying step, the carboxy-group containingfine cellulose fibers obtained in the step (a) are subjected to a finelypulverizing step.<43> The fine cellulose fiber composite according to any one of theabove <40> to <42>, wherein the amount of the above quaternaryalkylammonium compound in the step (b-1) used is an amount such that thequaternary alkylammonium cation is used in an amount of preferably 0.1mol or more, more preferably 0.5 mol or more, even more preferably 0.7mol or more, and still even more preferably 1 mol or more, andpreferably 50 mol or less, more preferably 20 mol or less, and even morepreferably 10 mol or less, based on 1 mol of the carboxy groupscontained in the carboxy group-containing fine cellulose fibers.<44> The fine cellulose fiber composite according to any one of theabove <40> to <43>, wherein the solvent used when mixing the carboxygroup-containing fine cellulose fibers and the quaternary alkylammoniumcompound in the step (b-1) is preferably water, a diester obtained fromsuccinic acid and triethylene glycol monomethyl ether, ethanol, and DMF.<45> The fine cellulose fiber composite according to any one of theabove <40> to <44>, wherein the temperature during mixing of the carboxygroup-containing fine cellulose fibers and the quaternary alkylammoniumcompound in the step (b-1) is preferably 0° C. or higher, morepreferably 5° C. or higher, and even more preferably 10° C. or higher,and preferably 50° C. or lower, more preferably 40° C. or lower, andeven more preferably 30° C. or lower.<46> The fine cellulose fiber composite according to any one of theabove <40> to <45>, wherein the mixing time of the carboxygroup-containing fine cellulose fibers and the quaternary alkylammoniumcompound in the step (b-1) is preferably 0.01 hours or more, morepreferably 0.1 hours or more, and even more preferably 1 hour or more,and preferably 48 hours or less, more preferably 24 hours or less, andeven more preferably 12 hours or less.<47> The fine cellulose fiber composite according to any one of theabove <40> to <46>, wherein the amount of the amine having an aromatichydrocarbon group used in the step (b-1) used is an amount such that theamine groups are used in an amount of preferably 0.1 mol or more, morepreferably 0.5 mol or more, even more preferably 0.7 mol or more, andstill even more preferably 1 mol or more, and preferably 50 mol or less,more preferably 20 mol or less, and even more preferably 10 mol or less,based on 1 mol of the carboxy groups contained in the carboxygroup-containing fine cellulose fibers.<48> The fine cellulose fiber composite according to any one of theabove <40> to <47>, wherein in the reaction of the carboxygroup-containing fine cellulose fibers with the amine having an aromatichydrocarbon group in the step (b-1), a known condensing agent can beused.<49> The fine cellulose fiber composite according to any one of theabove <40> to <48>, wherein in the reaction of the carboxygroup-containing fine cellulose fibers with the amine having an aromatichydrocarbon group in the step (b-1), a solvent can be used, and it ispreferable to select a solvent that dissolves an amine used.<50> The fine cellulose fiber composite according to any one of theabove <40> to <49>, wherein the temperature and time during the reactionof the carboxy group-containing fine cellulose fibers with the aminehaving an aromatic hydrocarbon group in the step (b-1) can be selectedfrom those as listed in the above <17>.<51> The fine cellulose fiber composite according to any one of theabove <40> to <50>, wherein the amount of the amine having an EO/POcopolymer moiety or a PO polymer moiety usable in the step (b-2) used isan amount such that the amine groups are used in an amount of preferably0.01 mol or more, more preferably 0.05 mol or more, even more preferably0.1 mol or more, even more preferably 0.5 mol or more, even morepreferably 0.7 mol or more, and still even more preferably 1 mol ormore, and preferably 50 mol or less, more preferably 20 mol or less, andeven more preferably 10 mol or less, based on one mol of carboxy groupscontained in the carboxy group-containing fine cellulose fibers.<52> The fine cellulose fiber composite according to any one of theabove <40> to <51>, wherein the temperature and time during the reactionin the step (b-2) can be selected from those as listed in the above<17>.<53> The fine cellulose fiber composite according to any one of theabove <20> to <52>, wherein the average fiber size of the fine cellulosefiber composite a is preferably 0.1 nm or more, more preferably 0.2 nmor more, even more preferably 0.5 nm or more, even more preferably 0.8nm or more, and still even more preferably 1 nm or more, and preferably200 nm or less, more preferably 100 nm or less, even more preferably 50nm or less, even more preferably 20 nm or less, and still even morepreferably 10 nm or less.<54> The fine cellulose fiber composite according to any one of theabove <20> to <53>, wherein it is preferable that the fine cellulosefiber composite a contains fine cellulose fibers, an EO/PO copolymermoiety or a PO polymer moiety, and a quaternary alkylammonium cationand/or an aromatic hydrocarbon, the fine cellulose fibers beingconnected with the copolymer moiety or the polymer moiety via an amidebond, being ionically bonded to the quaternary alkylammonium cationand/or amide-bonded to the aromatic hydrocarbon group, wherein theaverage fiber size is from 0.1 to 200 nm.<55> A fine cellulose fiber composite dispersion containing a finecellulose fiber composite as defined in any one of the above <1> to <54>and a plasticizer.<56> The fine cellulose fiber composite dispersion according to theabove <55>, wherein the content of the fine cellulose fiber composite inthe dispersion is preferably 0.01% by mass or more, more preferably0.03% by mass or more, even more preferably 0.05% by mass or more, andeven more preferably 0.1% by mass or more, and preferably 70% by mass orless, more preferably 50% by mass or less, even more preferably 30% bymass or less, even more preferably 10% by mass or less, even morepreferably 5% by mass or less, and even more preferably 3% by mass orless.<57> The fine cellulose fiber composite dispersion according to theabove <55> or <56>, wherein the amount of the fine cellulose fibers(conversion amount) is preferably 0.01% by mass or more, more preferably0.03% by mass or more, even more preferably 0.05% by mass or more, evenmore preferably 0.08% by mass or more, and even more preferably 0.1% bymass or more, and preferably 30% by mass or less, more preferably 20% bymass or less, even more preferably 10% by mass or less, even morepreferably 5% by mass or less, even more preferably 1% by mass or less,even more preferably 0.5% by mass or less, and still even morepreferably 0.3% by mass or less of the dispersion.<58> The fine cellulose fiber composite dispersion according to any oneof the above <55> to <57>, wherein the content of the plasticizer in thedispersion is preferably 95% by mass or more, more preferably 97% bymass or more, even more preferably 99% by mass or more, and still evenmore preferably 99.5% by mass or more, and preferably 99.95% by mass orless, more preferably 99.9% by mass or less, and even more preferably99.8% by mass or less.<59> A resin composition containing a thermoplastic resin or a curableresin and a fine cellulose fiber composite as defined in any one of theabove <1> to <54>.<60> The resin composition according to the above <59>, wherein thethermoplastic resin is preferably one or more members selected from thegroup consisting of saturated polyester-based resins such as polylacticacid resin; olefinic resins such as polyethylene-based resins andpolypropylene-based resins; cellulose-based resins such as triacetylatedcellulose and diacetylated cellulose; nylon resins, vinyl chlorideresins, styrene resins, (meth)acrylic resins, vinyl ether resins,polyvinyl alcohol resins, polyamide-based resins, polycarbonate-basedresins, polysulfonate-based resins, and the like, and more preferablythe polyester-based resins and the (meth)acrylic resins.<61> The resin composition according to the above <60>, wherein thepolyester-based resin is preferably one or more members selected fromthe group consisting of aliphatic polyester resins such as polyhydroxybutyrate, polycaprolactone, polybutylene succinate, polybutylenesuccinate/adipate, polyethylene succinate, polylactic acid resin,polymalic acid, polyglycolic acid, polydioxanone, and poly(2-oxetanone);aliphatic aromatic co-polyester resins such as polybutylenesuccinate/terephthalate, polybutylene adipate/terephthalate, andpolytetramethylene adipate/terephthalate; mixtures of a natural polymersuch as starch, cellulose, chitin, chitosan, gluten, gelatin, zain,soybean protein, collagen, or keratin, and the aliphatic polyesterresins or the aliphatic aromatic co-polyester resins mentioned above;and the like, more preferably the polybutylene succinate and thepolylactic acid resin, and even more preferably the polylactic acidresin.<62> The resin composition according to the above <60>, wherein the(meth)acrylic resin is preferably those containing 50% by weight or moreof methyl (meth)acrylate, on the basis of a total of the monomer unitsof the entire polymer constituting the resin, and more preferablymethacrylic resin.<63> The resin composition according to the above <59>, wherein thecurable resin is preferably a photo-curable resin and/or a thermosettingresin.<64> The resin composition according to the above <63>, wherein thephoto-curable resin is preferably obtained by polymerization with aphotopolymerization initiator, an oligomer or resin having one or morereactive unsaturated groups, selected from (meth)acrylates of alkyleneoxide adducts of bisphenol A, epoxy (meth)acrylates (bisphenol A typeepoxy (meth)acrylate, novolak type epoxy (meth)acrylate, etc.),polyester (meth)acrylates (e.g., aliphatic polyester-type(meth)acrylates, aromatic polyester-type (meth)acrylates, etc.),urethane (meth)acrylates (polyester-type urethane (meth)acrylates,polyether-type urethane (meth)acrylates, etc.), and silicone(meth)acrylates.<65> The resin composition according to the above <63> or <64>, whereinthe photopolymerization initiator used in the photo-curable resin ispreferably one or more members selected from the group consisting of1-hydroxy-cyclohexyl-phenyl-ketone,2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one, benzyl methylketone, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one,1-(4-isopropylphenyl)-2-hydroxy-2-hydroxy-2-methylpropan-1-one, andbenzophenone, and more preferably 1-hydroxy-cyclohexyl-phenyl-ketone.<66> The resin composition according to the above <63>, wherein thethermosetting resin is preferably one or more members selected from thegroup consisting of epoxy resins; phenol resins; urea resins; melamineresins; unsaturated polyester resins; diallyl phthalate resins;polyurethane resins; silicon-containing resins; polyimide resins;elastomeric resins, and more preferably epoxy resins.<67> The resin composition according to the above <66>, wherein theelastomeric resin is preferably diene-based rubbers, and more preferablynatural rubber (NR), polyisoprene rubber (IR), polybutadiene rubber(BR), styrene-butadiene copolymer rubber (SBR), butyl rubber (IIR),butadiene-acrylonitrile copolymer rubber (NBR), and modified naturalrubbers, and the like, wherein the modified natural rubber includesepoxidized natural rubber, hydrogenated natural rubber, and the like,and these can be used alone or in a combination of two or more kinds,and one or more members selected from natural rubber (NR), polyisoprenerubber (IR), polybutadiene rubber (BR), and styrene-butadiene copolymerrubber (SBR) are even more preferred, and one or more members selectedfrom natural rubber (NR), styrene-butadiene copolymer rubber (SBR), andmodified natural rubbers are more preferred.<68> The resin composition according to any one of the above <59> to<67>, wherein in the resin composition,the content of the resin is preferably 50% by mass or more, morepreferably 60% by mass or more, 70% by mass or more, even morepreferably 80% by mass or more, and even more preferably 85% by mass ormore, and preferably 99% by mass or less, more preferably 98% by mass orless, even more preferably 95% by mass or less, and even more preferably93% by mass or less;the content of the fine cellulose fiber composite is preferably 0.01% bymass or more, more preferably 0.05% by mass or more, even morepreferably 0.1% by mass or more, even more preferably 0.3% by mass ormore, even more preferably 0.5% by mass or more, even more preferably 1%by mass or more, even more preferably 2% by mass or more, and even morepreferably 3% by mass or more, and preferably 50% by mass or less, morepreferably 40% by mass or less, even more preferably 30% by mass orless, even more preferably 20% by mass or less, and still even morepreferably 15% by mass or less;the amount of the fine cellulose fiber composite, based on 100 parts bymass of the resin, is preferably 0.01 parts by mass or more, morepreferably 0.05 parts by mass or more, even more preferably 0.1 parts bymass or more, even more preferably 0.3 parts by mass or more, even morepreferably 0.5 parts by mass or more, even more preferably 1 part bymass or more, and still even more preferably 3 parts by mass or more,and preferably 60 parts by mass or less, more preferably 50 parts bymass or less, even more preferably 40 parts by mass or less, even morepreferably 30 parts by mass or less, even more preferably 20 parts bymass or less, and even more preferably 15 parts by mass or less; andthe amount of the fine cellulose fibers (conversion amount), based on100 parts by mass of the resin, is preferably 0.01 parts by mass ormore, more preferably 0.05 parts by mass or more, and even morepreferably 0.08 parts by mass or more, and preferably 60 parts by massor less, more preferably 50 parts by mass or less, even more preferably40 parts by mass or less, even more preferably 30 parts by mass or less,even more preferably 20 parts by mass or less, even more preferably 15parts by mass or less, and even more preferably 10 parts by mass orless.<69> The resin composition according to any one of the above <59> to<62> and <68>, wherein in a case where the resin is a thermoplasticresin, in the resin composition,the content of the resin is preferably 50% by mass or more, morepreferably 60% by mass or more, even more preferably 70% by mass ormore, even more preferably 80% by mass or more, and even more preferably85% by mass or more, and preferably 99% by mass or less, more preferably98% by mass or less, even more preferably 95% by mass or less, even morepreferably 93% by mass or less, even more preferably 90% by mass orless, and even more preferably 87% by mass or less;the amount of the fine cellulose fiber composite, based on 100 parts bymass of the resin, is preferably 0.01 parts by mass or more, morepreferably 0.05 parts by mass or more, even more preferably 0.1 parts bymass or more, even more preferably 0.5 parts by mass or more, even morepreferably 1 part by mass or more, even more preferably 3 parts by massor more, even more preferably 6 parts by mass or more, and even morepreferably 10 parts by mass or more, and preferably 100 parts by mass orless, more preferably 70 parts by mass or less, even more preferably 50parts by mass or less, even more preferably 40 parts by mass or less,even more preferably 30 parts by mass or less, even more preferably 20parts by mass or less, even more preferably 15 parts by mass or less,even more preferably 5 parts by mass or less, even more preferably 3parts by mass or less, even more preferably 1 part by mass or less, evenmore preferably 0.5 parts by mass or less, and even more preferably 0.3parts by mass or less; andthe amount of the fine cellulose fibers (conversion amount), based on100 parts by mass of the resin, is preferably 0.01 parts by mass ormore, more preferably 0.05 parts by mass or more, even more preferably0.08 parts by mass or more, even more preferably 0.1 parts by mass ormore, even more preferably 0.3 parts by mass or more, even morepreferably 0.5 parts by mass or more, even more preferably 2 parts bymass or more, and even more preferably 5 parts by mass or more, andpreferably 60 parts by mass or less, more preferably 50 parts by mass orless, even more preferably 40 parts by mass or less, even morepreferably 35 parts by mass or less, even more preferably 30 parts bymass or less, even more preferably 20 parts by mass or less, even morepreferably 15 parts by mass or less, even more preferably 10 parts bymass or less, even more preferably 5 parts by mass or less, even morepreferably 3 parts by mass or less, even more preferably 1 part by massor less, even more preferably 0.5 parts by mass or less, and even morepreferably 0.3 parts by mass or less.<70> The resin composition according to any one of the above <59>, <63>to <65>, and <68>, wherein in a case where the resin is a photo-curableresin, in the resin composition,the content of the resin is preferably 50% by mass or more, morepreferably 60% by mass or more, even more preferably 70% by mass ormore, even more preferably 80% by mass or more, and even more preferably85% by mass or more, and preferably 99% by mass or less, more preferably98% by mass or less, even more preferably 96% by mass or less, and evenmore preferably 93% by mass or less;the amount of the fine cellulose fiber composite, based on 100 parts bymass of the resin, is preferably 0.01 parts by mass or more, morepreferably 0.05 parts by mass or more, even more preferably 0.1 parts bymass or more, even more preferably 0.5 parts by mass or more, even morepreferably 1 part by mass or more, even more preferably 3 parts by massor more, even more preferably 6 parts by mass or more, and still evenmore preferably 10 parts by mass or more, and preferably 100 parts bymass or less, more preferably 70 parts by mass or less, even morepreferably 50 parts by mass or less, even more preferably 40 parts bymass or less, even more preferably 30 parts by mass or less, even morepreferably 20 parts by mass or less, even more preferably 15 parts bymass or less, and even more preferably 10 parts by mass or less; andthe amount of the fine cellulose fibers (conversion amount), based on100 parts by mass of the resin, is preferably 0.01 parts by mass ormore, more preferably 0.05 parts by mass or more, even more preferably0.1 parts by mass or more, even more preferably 0.5 parts by mass ormore, even more preferably 0.8 parts by mass or more, even morepreferably 1 part by mass or more, even more preferably 3 parts by massor more, and still even more preferably 5 parts by mass or more, andpreferably 50 parts by mass or less, more preferably 40 parts by mass orless, even more preferably 35 parts by mass or less, even morepreferably 30 parts by mass or less, even more preferably 20 parts bymass or less, even more preferably 15 parts by mass or less, and evenmore preferably 10 parts by mass or less.<71> The resin composition according to any one of the above <59>, <63>,and <66> to <68>, wherein in a case where the resin is a thermosettingresin, in the resin composition,the content of the resin is preferably 50% by mass or more, morepreferably 60% by mass or more, even more preferably 70% by mass ormore, even more preferably 80% by mass or more, and even more preferably85% by mass or more, and preferably 99% by mass or less, more preferably98% by mass or less, even more preferably 96% by mass or less, even morepreferably 90% by mass or less, even more preferably 85% by mass orless, and even more preferably 80% by mass or less;the amount of the fine cellulose fiber composite, based on 100 parts bymass of the resin, is preferably 0.01 parts by mass or more, morepreferably 0M5 parts by mass or more, even more preferably 0.1 parts bymass or more, even more preferably 0.5 parts by mass or more, even morepreferably 1 part by mass or more, even more preferably 3 parts by massor more, even more preferably 7 parts by mass or more, even morepreferably 10 parts by mass or more, and even more preferably 15 partsby mass or more, and preferably 100 parts by mass or less, morepreferably 70 parts by mass or less, even more preferably 50 parts bymass or less, even more preferably 40 parts by mass or less, even morepreferably 30 parts by mass or less, even more preferably 20 parts bymass or less, even more preferably 15 parts by mass or less, and evenmore preferably 10 parts by mass or less; andthe amount of the fine cellulose fibers (conversion amount), based on100 parts by mass of the resin, is preferably 0.01 parts by mass ormore, more preferably 0.05 parts by mass or more, even more preferably0.08 parts by mass or more, even more preferably 0.1 parts by mass ormore, even more preferably 0.5 parts by mass or more, even morepreferably 0.8 parts by mass or more, even more preferably 1 part bymass or more, even more preferably 3 parts by mass or more, even morepreferably 5 parts by mass or more, and even more preferably 8 parts bymass or more, and preferably 50 parts by mass or less, more preferably40 parts by mass or less, even more preferably 35 parts by mass or less,even more preferably 30 parts by mass or less, even more preferably 20parts by mass or less, even more preferably 15 parts by mass or less,even more preferably 10 parts by mass or less, even more preferably 5parts by mass or less, and even more preferably 3 parts by mass or less.<72> The resin composition according to any one of the above <59> to<71>, wherein the resin composition can be prepared by subjecting rawmaterials containing a thermoplastic resin or a curable resin and a finecellulose fiber composite, and further optionally various additives tomelt-kneading or a solvent casting method.<73> The resin composition according to any one of the above <59> to<72>, which can be suitably used in various applications such as dailysundries, household electric appliance parts, and automobile parts, andespecially more suitably used in automobile applications.<74> A resin molded article which can be prepared by subjecting a resincomposition as defined in any one of the above <59> to <73> to moldingsuch as extrusion molding, injection molding, or press molding.<75> The molded article according to the above <74>, wherein the moldedarticle is in a sheet-like form, and has a thickness of preferably 0.05mm or more, more preferably 0.1 mm or more, and even more preferably0.15 mm or more, and preferably 1.5 mm or less, more preferably 1.0 mmor less, and even more preferably 0.5 mm or less.

EXAMPLES

The present invention will be described more specifically by means ofthe following Examples and Comparative Examples, without intending tolimit the scope of the present invention to the following Examples.

[Average Fiber Size of Fine Cellulose Fibers]

Water is added to fine cellulose fibers to provide a dispersion of whichconcentration is 0.0001% by mass. The dispersion is added dropwise tomica (mica), and dried to provide an observation sample. A fiber heightof the cellulose fibers in the observation sample is measured with anatomic force microscope (AFM, Nanoscope III Tapping mode AFM,manufactured by Digital Instrument, a probe used being Point Probe (NCH)manufactured by NANOSENSORS. During that measurement, five or more setsof fine cellulose fibers are extracted from a microscopic image in whichthe cellulose fibers can be confirmed, and an average fiber size iscalculated from those fiber heights.

[Carboxy Group Contents of Fine Cellulose Fibers and Fine CelluloseFiber Composite]

Fine cellulose fibers or a fine cellulose fiber composite with the massof 0.5 g on a dry basis is placed in a 100 mL beaker, a mixed solvent of(ion-exchanged water or methanol)/water=2/1 is added thereto to make upa total volume of 55 mL. Five milliliters of a 0.01 M aqueous sodiumchloride solution is added thereto to provide a dispersion, and thedispersion is stirred until the fine cellulose fibers or the finecellulose fiber composite is sufficiently dispersed. A 0.1 Mhydrochloric acid is added to this dispersion to adjust its pH to 2.5 to3, and a 0.05 M aqueous sodium hydroxide solution is added dropwise tothe dispersion with an automated titration instrument manufactured byDKK-TOA CORPORATION under the trade name of “AUT-50,” under theconditions of a waiting time of 60 seconds. The values ofelectroconductivity and a pH are measured every minute, and themeasurements are continued up to a pH of 11 or so to obtain anelectroconductivity curve. A titrated amount of sodium hydroxide isobtained from this electroconductivity curve, and the carboxy groupcontent of the fine cellulose fibers or the fine cellulose fibercomposite is calculated in accordance with the following formulas:

Carboxy Group Content (mmol/g)=Titrated Amount of SodiumHydroxide×Aqueous Sodium Hydroxide Solution Concentration (0.05 M)/Massof Cellulose Fibers (0.5 g)

[Average Binding Amount and Modification Ratio (Amide-Formation Ratio)of Amide Group Having EO/PO Copolymer Moiety or PO Polymer Moiety ofFine Cellulose Fiber Composite]

The average binding amount of the amide group having an EO/PO copolymermoiety or a PO polymer moiety in the fine cellulose fiber composite iscalculated by the following formula.

Binding Amount of Amide Group Having EO/PO Copolymer Moiety or POPolymer Moiety (mmol/g)=Carboxy Group Content of Fine Cellulose FibersBefore Introducing Amide Group (mmol/g)−Carboxy Group Content of FineCellulose Fibers After Introducing Amide Group (mmol/g)

Modification Ratio (%) (Amide-Formation Ratio (%))={Binding Amount ofthe Amide Group (mmol/g)/Carboxy Group Content (mmol/g) in FineCellulose Fibers Before Introducing the Amide Group}×100

Preparation Example 1 Of Fine Cellulose Fibers—Dispersion of CarboxyGroup-Containing Fine Cellulose Fibers Obtained by Treating NaturalCellulose with N-Oxyl Compound

Needle-leaf bleached kraft pulp manufactured by Fletcher ChallengeCanada Ltd., under the trade name of “Machenzie,” CSF 650 ml, was usedas natural cellulose fibers. As TEMPO, a commercially available productmanufactured by ALDRICH, Free radical, 98% by mass, was used. As sodiumhypochlorite, a commercially available product manufactured by Wako PureChemical Industries, Ltd. was used. As sodium bromide, a commerciallyavailable product manufactured by Wako Pure Chemical Industries, Ltd.was used.

First, 100 g of the needle-leaf bleached kraft pulp fibers weresufficiently stirred in 9,900 g of ion-exchanged water, and 1.25% bymass of TEMPO, 12.5% by mass of sodium bromide, and 28.4% by mass ofsodium hypochlorite were added in that order to 100 g of the mass of thepulp. Using a pH stud, a 0.5 M sodium hydroxide was added dropwise tokeep a pH at 10.5. After the reaction was carried out at 20° C. for 120minutes, the dropwise addition of sodium hydroxide was stopped, toprovide oxidized pulp. The oxidized pulp obtained was sufficientlywashed with ion-exchanged water, and subsequently subjected to adehydration treatment. Thereafter, 3.9 g of the oxidized pulp and 296.1g of ion-exchanged water were subjected twice to a finely pulverizingtreatment with a high-pressure homogenizer manufactured by SuginoMachine Limited, Starburstlabo HJP-2 5005 at 245 MPa, to provide adispersion of carboxy group-containing fine cellulose fibers, a solidcontent concentration of which was 1.3% by mass. The resulting finecellulose fibers had an average fiber size of 3.3 nm and a carboxy groupcontent of 1.4 mmol/g.

Preparation Example 2 Of Fine Cellulose Fibers—Dispersion of CarboxyGroup-Containing Fine Cellulose Fibers Obtained by Acidic Treatment

In a beaker, 4,085 g of ion-exchanged water was added to 4,088.75 g of adispersion of carboxy group-containing fine cellulose fibers obtained inPreparation Example 1, a solid content concentration of which was 1.3%by mass, to provide a 0.5% by mass aqueous solution, and the aqueoussolution was stirred with a mechanical stirrer at room temperature, 25°C., for 30 minutes. Next, the beaker was charged with 245 g of a 1 Maqueous hydrochloric acid solution, and the contents were allowed toreact for 1 hour at room temperature. After the termination of thereaction, the reaction mixture was reprecipitated with acetone, theprecipitates were filtered, and thereafter the residue was washed withacetone/ion-exchanged water, to remove hydrochloric acid and salt.Finally, acetone was added thereto, and the mixture was filtered, toprovide a dispersion of acetone-containing acidic cellulose fibers in astate that the carboxy group-containing fine cellulose fibers wereswollen with acetone, a solid content concentration of which was 5.0% bymass. After the termination of the reaction, the reaction mixture wasfiltered, and thereafter the residue was washed with ion-exchanged waterto remove hydrochloric acid and salt. The washed mixture was subjectedto a solvent replacement with acetone, and thereafter subjected to asolvent replacement with IPA, to provide a dispersion of IPA-containingacidic cellulose fibers in a state that the carboxy group-containingfine cellulose fibers were swollen, a solid content concentration ofwhich was 5.0% by mass. The resulting fine cellulose fibers had anaverage fiber size of 3.3 nm and a carboxy group content of 1.4 mmol/g.

Preparation Example 1 Of Plasticizer—Diester Obtained from Succinic Acidand Triethylene Glycol Monomethyl Ether

A 3-L flask equipped with a stirrer, a thermometer, and a dehydrationtube was charged with 500 g of succinic anhydride, 2,463 g oftriethylene glycol monomethyl ether, and 9.5 g of paratoluenesulfonicacid monohydrate, and the contents were allowed to react at 110° C. for15 hours under a reduced pressure of from 4 to 10.7 kPa, while blowingnitrogen at 500 mL/min in a space portion. The liquid reaction mixturehad an acid value of 1.6 mgKOH/g. To the liquid reaction mixture wasadded 27 g of an adsorbent KYOWAAD 500SH manufactured by Kyowa ChemicalIndustry Co., Ltd., and the mixture was stirred at 80° C. and 2.7 kPafor 45 minutes, and filtered. Thereafter, triethylene glycol monomethylether was distilled off at a liquid temperature of from 115° to 200° C.and a pressure of 0.03 kPa, and after cooling to 80° C., the residualliquid was filtered under a reduced pressure, to provide a diesterobtained from succinic acid and triethylene glycol monomethyl ether as afiltrate. The diester obtained had an acid value of 0.2 mgKOH/g, asaponification value of 276 mgKOH/g, a hydroxyl value of 1 mgKOH/g orless, and a hue APHA of 200.

Production Examples 1 to 9 Of Amines Having EO/PO Copolymer Moiety or POPolymer Moiety (Amine with EOPO Copolymer, Amine with PO Polymer)

A 1-L autoclave was charged with 132 g (1 mol) of propylene glycoltertiary butyl ether, and the content was heated to 75° C., 1.2 g of aflake-like potassium hydroxide was added thereto, and stirred untilbeing dissolved. Next, ethylene oxide (EO) and propylene oxide (PO) inamounts as listed in Table 1 were allowed to react therewith at 110° C.and 0.34 MPa, and 7.14 g of magnesium silicate Magnesol 30/40,manufactured by Dallas Group of America was then introduced thereto. Themixture was neutralized at 95° C., and 0.16 g of di-tertiarybutyl-p-cresol was added to the reaction product obtained and mixed, andthereafter filtered to provide a polyether, an EO/PO copolymer or a POpolymer.

On the other hand, the polyether obtained above was fed at 8.4 mL/min,ammonia at 12.6 mL/min and hydrogen at 0.8 mL/min, respectively, to a1.250 mL tubular reaction vessel filled with catalysts of nickeloxide/copper oxide/chromium oxide at a molar ratio of 75/23/2,manufactured by Wako Pure Chemicals Industries, Ltd. The temperature ofthe reaction vessel was maintained at 190° C., and the pressure wasmaintained at 14 MPa. Thereafter, a crude discharged liquid from thevessel was distilled off at 70° C. and 3.5 mmHg for 30 minutes. A flaskwas charged with 200 g of the amino-forming polyether obtained and 93.6g of a 15% aqueous hydrochloric acid solution, the reaction mixture washeated at 100° C. for 3.75 hours, to allow the tertiary butyl ether toopen with the acid. Subsequently, the product was neutralized with 144 gof a 15% aqueous potassium hydroxide solution. Next, the neutralizedproduct was distilled off at 112° C. under a reduced pressure for onehour, and the residue was filtered, to provide a monoamine having anEO/PO copolymer moiety or a PO polymer represented by the formula (i).Here, in the monoamine obtained the EO/PO copolymer moiety or the POpolymer and the amine are directly bound, and R₁ in the formula (i) is ahydrogen atom.

Here, the molecular weight of the amine with a copolymer moiety wascalculated, for example, in a case of the amine of Production Example 1,as follows:

2,201 [molecular weight of EO (44.03)×number of moles of EO added(50)]+697 [molecular weight of PO (58.04)×number of moles of PO added(12.0)]+58.04 [molecular weight of PO moiety of the starting rawmaterials (propylene glycol)]=2,956,

which was rounded up to 3,000.

Production Examples 1-1 to -11 Of Fine Cellulose FiberComposite—Examples 1-1 to -9 and Comparative Examples 1-1 to -2

A beaker equipped with a magnetic stirrer and a stirring bar was chargedwith 35 g of a dispersion of carboxy group-containing fine cellulosefibers, of which solid content was 5.4% by mass, obtained in PreparationExample 2 of Fine Cellulose Fibers. Subsequently, the beaker was chargedwith an amine of the kinds as listed in Tables 1 and 2 each in an amountcorresponding to 5 mol of amine groups based on one mol of carboxygroups of the fine cellulose fibers, and 3.78 g of4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride(DMT-MM), a condensing agent, and dissolved in 300 g of IPA. The liquidreaction mixture was allowed to react at room temperature, 25° C., for14 hours. After the termination of the reaction, the reaction mixturewas filtered, washed with ion-exchanged water to remove a DMT-MM salt,and washed with acetone, and subjected to solvent replacement, toprovide a fine cellulose fiber composite in which the fine cellulosefibers were connected with an EOPO copolymer or a PO polymer, a PEGchain, or a propyl group via an amide bond.

Production Example 1-12 Of Fine Cellulose Fiber Composite—ComparativeExample 1-3

A beaker equipped with a magnetic stirrer and a stirring bar was chargedwith 35 g of a dispersion of carboxy group-containing fine cellulosefibers, of which solid content was 5.4% by mass, obtained in PreparationExample 2 of Fine Cellulose Fibers. Subsequently, the beaker was chargedwith 0.8 g of propylamine, an amount corresponding to 5 mol of aminegroups based on one mol of carboxy groups of the fine cellulose fibers,and dissolved in 300 g of ethanol. The liquid reaction mixture wasallowed to react at room temperature, 25° C., for 6 hours. After thetermination of the reaction, the reaction mixture was filtered, washedwith acetone, and subjected to solvent replacement, to provide a finecellulose fiber composite in which the fine cellulose fibers wereconnected with a propyl group via an ionic bond.

Preparation Examples 1-1 to -12 Of Dispersion of Fine Cellulose FiberComposite—Examples 1-1 to -9 and Comparative Examples 1-1 to -3

Fine cellulose fibers in the fine cellulose fiber composite of the kindsas listed in Tables 1 and 2 in an amount corresponding to 0.04 gaccording to the following formula, and 40 g of a diester obtained fromsuccinic acid and triethylene glycol monomethyl ether, synthesized inPreparation Example 1 of Plasticizer, as a dispersant were mixed, andstirred with a ultrasonic homogenizer US-300E, manufactured byNIHONSEIKI KAISHA, LTD. for 2 minutes. Thus, a dispersion of the finecellulose fiber composite containing a fine cellulose fiber compositeand a plasticizer was prepared, of which fine cellulose fiberconcentration was 0.10% by mass. Here, the molecular weight of the amineas referred to herein is a molecular weight of the entire amine compoundincluding the copolymer moiety.

Amount of Fine Cellulose Fibers (g)=Fine Cellulose Fiber Composite(g)/[1+Molecular Weight of Amine (g/mol)×Binding Amount of Amine(mmol/g)×0.001]

The properties of the dispersion of the fine cellulose fiber compositeobtained were evaluated in accordance with the methods of the followingTest Examples 1 to 3. The results are shown in Tables 1 and 2.

Test Example 1 Amount of Aggregates

The dispersion of the fine cellulose fiber composite obtained wasobserved in a crossed Nicol state using transmitting light with adigital microscope VHX-1000, manufactured by KEYENCE. The image analysiswas performed using WINROOF manufactured by MITANI CORPORATION tocalculate an area of aggregates. Specifically, the image obtained wasmonochromatized, and converted to a binary image, and areas of whiteportions were calculated. The lower the numerical value, the moreexcellent the transparency.

Test Example 2 Transmittance

Transmittance of the dispersion of the fine cellulose fiber compositeobtained was measured at 600 nm using a ultraviolet-visiblespectrophotometer, UV-VISIBLE SPECTROMETER UV-2550, manufactured byShimadzu Corporation, and this was used as an index for transparency.The higher the numerical value, the more excellent the transparency.

Test Example 3 Thermal Degradation Temperature

The dispersion of the fine cellulose fiber composite obtained was driedunder a reduced pressure at 60° C. overnight, and thereafter thetemperature was raised from 25° to 500° C. at a rate of 10° C./minute,using a thermogravimetric analyzer TG-DTA6300 manufactured by SeikoInstruments, Inc. A temperature at a point where the weight is 5%reduced from that at 100° C. is defined as a thermal degradationtemperature, which was used as an index for thermal stability. Thehigher the numerical value, the more excellent the thermal stability.

TABLE 1 Examples 1-1 1-2 1-3 1-4 1-5 Amine Kinds Amine Amine Amine AmineAmine with with with with with EO/PO EO/PO EO/PO EO/PO EO/PO CopolymerCopolymer Copolymer Copolymer Copolymer Production Example No. of Amine1 2 3 4 5 with EO/PO Copolymer Amount of EO used, g, number of mol 2,201g, 1,893 g, 1,761 g, 1,409 g, 837 g, 50.0 mol 43.0 mol 40.0 mol 32.0 mol19.0 mol a of formula (i) 50.0 43.0 40.0 32.0 19.0 Amount of PO used, g,number of mol 697 g, 58 g, 174 g, 523 g, 1,104 g, 12.0 mol 1.0 mol 3.0mol 9.0 mol 19.0 mol b of formula (i) ⁽¹⁾ 13.0 2.0 4.0 10.0 20.0 POContent Ratio, % by mol, b × 100/(a + b) 21 4 9 24 51 Molecular Weightof Copolymer Moiety 3,000 2,000 2,000 2,000 2,000 Fine Binding Amount ofAmide, mmol/g 0.28 0.36 0.39 0.38 0.39 Cellulose Fiber Amide-FormationRatio, % 20 26 28 27 28 Composite Plasticizer Amount of Aggregates, ×10⁴μm² 0.5 0.8 0.4 0.4 0.6 Dispersion Transmittance, % 98 95 99 99 97Thermal Degradation Temperature, ° C. 286 283 282 282 283 Examples 1-61-7 1-8 1-9 Amine Kinds Amine Amine Amine Amine with with with PO withEO/PO EO/PO Polymer EO/PO Copolymer Copolymer Copolymer ProductionExample No. of Amine 6 7 8 9 with EO/PO Copolymer Amount of EO used, g,number of mol 396 g, 88 g, 0 g, 881 g, 9.0 mol 2.0 mol 0 mol 20.0 mol aof formula (i) 9.0 2.0 0 20.0 Amount of PO used, g, number of mol 1,568g, 1,859 g, 1,975 g, 58 g, 27.0 mol 32.0 mol 34.0 mol 1.0 mol b offormula (i) ⁽¹⁾ 28.0 33.0 35.0 2.0 PO Content Ratio, % by mol, b ×100/(a + b) 76 94 100 9 Molecular Weight of Copolymer Moiety 2,000 2,0002,000 1,000 Fine Binding Amount of Amide, mmol/g 0.39 0.38 0.36 0.42Cellulose Fiber Amide-Formation Ratio, % 28 27 26 30 CompositePlasticizer Amount of Aggregates, ×10⁴ μm² 0.8 0.9 1.0 0.5 DispersionTransmittance, % 95 94 93 98 Thermal Degradation Temperature, ° C. 283283 283 278 ⁽¹⁾ The number of moles totaling 1 mol of propylene glycolfrom tert-butyl ether of propylene glycol, the raw material.

TABLE 2 Comparative Examples 1-1 1-2 1-3 Amine Kinds PEG Amine n-Propyl-n-Propyl- amine amine Molecular Weight 2,000 59 59 Amount, g 30.46 g1.35 g 0.80 g Binding Form Amide Bond Amide Bond Ionic Bond Fine BindingAmount 038 0.88 — Cellulose of Amide Group, Fiber mmol/g CompositeAmide-Formation 27 63 — Ratio, % Plasticizer Amount of 2.0 2.4 3.1Dispersion Aggre- gates, ×10⁴ μm² Transmittance, % 83 79 72 Thermal 280215 195 Degradation Temperature, ° C. * PEG Amine: average molecularweight: 2,000, SUNBRIGHT, MEPA-20H, manufactured by NOF Corporationn-Propylamineamine: C3 amine, manufactured by Wako Pure ChemicalIndustries, Ltd.

It could be seen from Tables 1 and 2, from the results of thecomparisons of Example 1-1 and Example 1-4, even while the PO contentratio in the copolymer moiety was nearly the same, if the molecularweight of the copolymer increased from 2,000 to 3,000, the heatresistance slightly improves, even though the amount of aggregates wasslightly increased, and the transmittance was slightly lowered. Inaddition, from the comparison of Example 1-3 and Example 1-9, even whilethe PO content ratio in the copolymer moiety was the same, if themolecular weight of the copolymer was decreased from 2,000 to 1,000, theamount of aggregates slightly increased, the transmittance was alsoslightly lowered, and the heat resistance was also slightly lowered.

From the results of the comparisons of Examples 1-2 to -8, even whilethe molecular weight of the copolymer was 2,000, which was the same,Examples 1-3 and 1-4 where the PO content ratios in the copolymer moietywere 9 and 24% by mol gave the least amount of aggregates and also hightransmittance. On the other hand, Comparative Examples 1-1 and 1-2 whereamide-formation was carried out with PEG amine or n-propylamine gave aconsiderably increased amount of aggregates, and lowered transmittance.Also, it could be seen that a case of Comparative Example 1-3 where anamine salt is formed with n-propylamine gave a larger amount ofaggregates and clearly lowered transmittance and heat resistance.

Example 1-10 Thermoplastic Resin 1

The fine cellulose fiber composite used in Example 1-4 in an amount assolid content conversion of 0.16 g, and 10 g of a diester obtained fromsuccinic acid and triethylene glycol monomethyl ether, synthesized inPreparation Example 1 of Plasticizer as a dispersant were mixed, andstirred with the ultrasonic homogenizer US-300E for 3 minutes, toprovide a dispersion of the fine cellulose fiber composite, of whichfine cellulose fiber composite concentration (conversion amount) wasabout 1% by mass, the dispersion containing the fine cellulose fibercomposite and a plasticizer. The amount 10.16 g of this dispersion ofthe fine cellulose fiber composite and 100 g of a polylactic acid resin,manufactured by Nature works, trade name of N4000, were sequentiallyadded, and the mixture was kneaded with a kneader manufactured by TOYOSEIKI SEISAKU-SHO, trade name “Labo-plastomill,” under conditions of arotational speed of 50 rpm, and 180° C. for 10 minutes to provide ahomogeneous mixture. The homogeneous mixture was sequentially pressedwith a press machine manufactured by TOYO SEIKI SEISAKU-SHO, trade name“Labo-press,” under conditions of at 180° C. and 0.5 MPa for 2 minutes,at 20 MPa for 2 minutes, at 0.5 MPa for 1 minute, and then at 80° C. and0.5 MPa for 2 minutes, to provide a sheet-like composite material havinga thickness of about 0.4 mm.

Comparative Example 1-4

The same procedures as in Example 1-8 were carried out except that adispersion of a fine cellulose fiber composite was not used, and 10 g ofa plasticizer alone was used, to provide a composite material.

Comparative Example 1-5

The same procedures as in Example 1-10 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Comparative Example 1-1, to provide a composite material.

Comparative Example 1-6

The same procedures as in Example 1-10 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Comparative Example 1-2, and that the amount of thedispersion of the fine cellulose fiber composite was changed such thatthe amount of the fine cellulose fibers was in an amount as listed inTable 3 to provide a composite material.

Comparative Example 1-7

The same procedures as in Example 1-10 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Comparative Example 1-3, and that the amount of thedispersion of the fine cellulose fiber composite was changed such thatthe amount of the dispersion of the fine cellulose fiber composite wasin an amount as listed in Table 3 to provide a composite material.

The properties of the molded article obtained were evaluated inaccordance with the methods of the above Test Examples 4 and 5. Theresults are shown in Table 3. In Table 3, the conversion amount of thefine cellulose fibers was obtained by the above formula.

Test Example 4 Tensile Modulus

Each of the tensile modulus and the tensile strength at yield of themolded article was measured in accordance with a tensile test asprescribed in JIS K7113 using a tensile compression testing machinemanufactured by SHIMADZU CORPORATION, under the trade name of presence“Autograph AGS-X”. Samples punched through with No. 2 dumbbell were setat a span of 80 mm and measured at a crosshead speed of 50 mm/min. It isshown that the higher the tensile modulus, the more excellent themechanical strength.

Test Example 5 Transparency

Haze values were measured with a haze meter Model HM-150, manufacturedby MURAKAMI COLOR RESEARCH LABORATORY CO., Ltd., and the Haze valueswere used as indexes for transparency. It is shown that the lower thenumerical values, the more excellent the transparency.

TABLE 3 Example Comparative Examples 1-10 1-4 1-5 1-6 1-7 Amine KindsAmine with — PEG Amine n-Propylamine n-Propylamine EO/PO CopolymerProduction Example No. of Amine 4 — — — — with EO/PO Copolymer BindingForm Amide Bond — Amide Bond Amide Bond Ionic Bond Amount of PolylacticAcid Resin, parts by mass 100 100 100 100 100 Amount of Plasticizer,parts by mass 10 10 10 10 10 Amount of Fine Cellulose Fiber Composite,0.16 0 0.16 0.11 0.11 parts by mass Amount of Fine Cellulose Fibers,parts by mass, 0.09 0 0.09 0.10 0.10 Conversion Amount Content ofPolylactic Acid Resin 90.8 90.9 90.8 90.8 90.8 in Resin Composition, %by mass Content of Plasticizer in Resin 9.06 9.1 9.06 9.08 9.08Composition, % by mass Content of Fine Cellulose Fiber Composite 0.140.0 0.14 0.12 0.12 in Resin Composition, % by mass Properties TensileModulus, GPa 2.2 1.5 1.7 2.2 1.6 Haze, % 4 4 7 7 13 * PEG Amine: averagemolecular weight: 2,000, SUNBRIGHT, MEPA-20H, manufactured by NOFCorporation n-Propylamine: C3 amine, manufactured by Wako Pure ChemicalIndustries, Ltd.

It could be seen from Table 3 that from the comparison of Example 1-10and Comparative Examples 1-4 to -7, the thermoplastic resin compositioncontaining a fine cellulose fiber composite of the present inventionproduct can improve the mechanical strength of the resin composition,while maintaining the transparency.

Example 1-11 Photo-Curable Resin

A fine cellulose fiber composite used in Example 1-4 was subjected to asolvent replacement with dimethyl formamide (DMF), and a solid contentconcentration was adjusted to 4.3% by mass. The amount 3.5 g of thisdispersion of the fine cellulose composite, 10 g of a urethane acrylateresin UV-3310B manufactured by The Nippon Synthetic Chemical IndustryCo., Ltd., and 56 g of DMF were mixed, and the mixture was subjected toa finely pulverizing treatment using a high-pressure homogenizer underconditions of at 60 MPa in one pass and then at 100 MPa in one pass. Toa solution obtained was added 0.4 g of 1-hydroxy-cyclohexy-phenyl ketonemanufactured by Wako Pure Chemical Industries, Ltd. as aphotopolymerization initiator, and the mixture was stirred with aplanetary centrifugal agitator Awatori Rentaro manufactured by THINKYCORPORATION for 7 minutes. The varnish obtained was applied in a coatingthickness of 1.8 mm using a bar coater, and dried at 80° C. for 30minutes, to remove the solvents. The dried coating film was irradiatedusing a UV irradiation apparatus manufactured by Fusion Systems JapanCo., Ltd., Light Hammer10 at 200 mJ/cm² to allow photo-curing, toprovide a sheet-like composite material having a thickness of about 0.27mm.

Example 1-12

The same procedures as in Example 1-11 were carried out except that thedispersion of the fine cellulose fiber composite was changed from 3.5 gto 10.5 g, and DMF was changed from 56 g to 52 g, to provide a compositematerial.

Example 1-13

The same procedures as in Example 1-11 were carried out except that thedispersion of the fine cellulose fiber composite was changed from 3.5 gto 35 g, and DMF was changed from 56 g to 34 g, to provide a compositematerial.

Comparative Example 1-8

The same procedures as in Example 1-11 were carried out except that thefine cellulose fiber composite was not added, and DMF was changed from56 g to 58 g, to provide a composite material.

Comparative Example 1-9

The same procedures as in Example 1-11 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite used in Comparative Example 1-1, to provide a compositematerial.

Comparative Example 1-10

The same procedures as in Example 1-11 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite used in Comparative Example 1-2, and the amount of thedispersion was changed such that the fine cellulose fibers were added inan amount as listed in Table 4, to provide a composite material.

The properties of the molded article obtained were evaluated inaccordance with the methods of the above Test Examples 4 and 5 and thefollowing Test Examples 6 and 7. The results are shown in Table 4. InTable 4, the conversion amount of the fine cellulose fibers was obtainedby the above formula.

Test Example 6 Coefficient of Linear Thermal Expansion

Using a thermal stress-strain measurement apparatus manufactured bySEIKO INSTRUMENTS, under the trade name of “EXSTAR TMA/SS6100,”rectangular samples having sizes of a width of 3 mm and a length of 20mm were measured at a tensile mode with a load of 7 g while raising thetemperature at a rate of 5° C. per minute under nitrogen atmosphere. Thecoefficient of linear thermal expansion was obtained by calculating anaverage coefficient of linear thermal expansion within the temperaturerange of from room temperature, 25° C., to 150° C. It is shown that thelower the coefficient of the linear thermal expansion, the moreexcellent the dimensional stability.

Test Example 7 Storage Modulus

Using a dynamic viscoelastometer manufactured by SII, under the tradename of “DMS6100,” rectangular samples having sizes of a width of 5 mmand a length of 20 mm were subjected to measurement in a tensile modeunder nitrogen atmosphere at a frequency of 1 Hz, while raising thetemperature from −20° to 160° C. at a rate of 2° C. per minute. As thestorage modulus, the value at 100° C. was used. It is shown that thehigher the storage modulus, the more excellent the heat resistance.

TABLE 4 Examples Comparative Examples 1-11 1-12 1-13 1-8 1-9 1-10 AmineKinds Amine with Amine with Amine with — PEG Amine n-Propylamine EO/POEO/PO EO/PO Copolymer Copolymer Copolymer Production Example No. ofAmine 4 4 4 — — — with EO/PO Copolymer Binding Form Amide Bond AmideBond Amide Bond — Amide Bond Amide Bond Amount of Urethane-AcrylateResin, 100 100 100 100 100 100 parts by mass Amount of Fine CelluloseFiber Composite, 1.51 4.52 15.05 0 1.51 0.89 parts by mass Amount ofFine Cellulose Fibers, 0.86 2.57 8.55 0 0.86 0.85 parts by mass,Conversion Amount Content of Urethane-Acrylate Resin in Resin 98.5 95.786.9 100.0 98.5 99.1 Composition, % by mass Content of Fine CelluloseFiber Composite 1.5 4.3 13.1 0.0 1.5 0.9 in Resin Composition, % by massProperty Tensile Modulus, GPa 0.28 0.56 1.18 0.13 0.15 0.15 Haze, % 0.40.6 0.6 0.3 1.0 3.0 Coefficient of Linear Thermal 36 28 −10 150 150 140Expansion, ppm/K Storage Modulus at 100° C., ×10⁷ Pa 10.0 17.6 18.9 1.51.7 1.6 * PEG Amine: average molecular weight: 2,000, SUNBRIGHT,MEPA-20H, manufactured by NOF Corporation n-Propylamineamine: C3 amine,manufactured by Wako Pure Chemical Industries, Ltd.

From Table 4, it can be seen from the comparison of Example 1-11 andComparative Examples 1-8 to -10 that the photo-curable resin compositioncontaining the fine cellulose fiber composite of the present inventionproduct has a high mechanical strength, a high transparency, excellentdimensional stability, and also excellent heat resistance. In addition,it can be seen from the comparison of Examples 1-11 to -13 that evenwhen the content of the fine cellulose fiber composite is increased, thetransparency remains high without lowering, the mechanical strength ishigh, the dimensional stability is excellent, and the heat resistance isexcellent.

Example 1-14 Thermosetting Resin 1

A fine cellulose fiber composite used in Example 1-4 was subjected to asolvent replacement with DMF, and a solid content concentration wasadjusted to 0.4% by mass. The amount 9.4 g of this dispersion of thefine cellulose fiber composite and 2.5 g of an epoxy resin jER828manufactured by Mitsubishi Chemical Corporation were mixed, and themixture was subjected to a finely pulverizing treatment using ahigh-pressure homogenizer under conditions of at 60 MPa in one pass, andthen at 100 MPa in one pass. To a solution obtained was added 0.4 g of2-ethyl-4-methylimidazole manufactured by Wako Pure Chemical Industries,Ltd. as a curing agent, and the mixture was stirred with a planetarycentrifugal agitator Awatori Rentaro manufactured by THINKY CORPORATIONfor 7 minutes. The varnish obtained was applied in a coating thicknessof 0.85 mm using a bar coater, and dried at 100° C. for 1 hour, toremove the solvents. Thereafter, the coating film was thermally cured at150° C. for 2 hours, to provide a sheet-like composite material having athickness of about 0.2 mm.

Example 1-15

The same procedures as in Example 1-14 were carried out except that thedispersion of the fine cellulose fiber composite was changed from 9.4 gto 28.4 g, and that a coating film thickness was changed from 0.85 mm to2.1 mm to provide a composite material.

Comparative Example 1-11

The same procedures as in Example 1-14 were carried out except that thefine cellulose fiber composite was not added, and that a coating filmthickness was changed from 0.85 mm to 0.20 mm to provide a compositematerial.

Comparative Example 1-12

The same procedures as in Example 1-14 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite used in Comparative Example 1-1 to provide a compositematerial.

Comparative Example 1-13

The same procedures as in Example 1-14 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite used in Comparative Example 1-2, and that the amount of thedispersion was changed such that the fine cellulose fibers are in anamount as listed in Table 5 to provide a composite material.

The properties of the molded article obtained were evaluated inaccordance with the methods of the above Test Examples 4 to 7. Theresults are shown in Table 5. In Table 5, the conversion amount of thefine cellulose fibers was obtained by the above formula.

TABLE 5 Examples Comparative Examples 1-14 1-15 1-11 1-12 1-13 AmineKinds Amine with Amine with — PEG Amine n-Propylamine EO/PO EO/POCopolymer Copolymer Production Example No. of Amine 4 4 — — — with EO/POCopolymer Binding Form Amide Bond Amide Bond — Amide Bond Amide BondContent of Epoxy Resin, parts by mass 100 100 100 100 100 Content ofFine Cellulose Fiber Composite, 1.50 4.54 0 1.50 0.89 parts by massAmount of Fine Cellulose Fibers, 0.85 2.58 0 0.85 0.85 parts by mass,Conversion Amount Content of Epoxy Resin in Resin 98.5 95.7 100 98.599.1 Composition, % by mass Content of Fine Cellulose Fiber Composite1.5 4.3 0 1.5 0.9 in Resin Composition, % by mass Properties TensileModulus, GPa 2.8 3.2 2.5 2.6 2.6 Haze, % 4.9 8.4 1 10 15 Coefficient ofLinear Thermal 51 35 63 62 63 Expansion, ppm/K Storage Modulus at 100°C., ×10⁷ Pa 163 225 130 135 133 * PEG Amine: average molecular weight:2,000, SUNBRIGHT, MEPA-20H, manufactured by NOF Corporationn-Propylamine: C3 amine, manufactured by Wako Pure Chemical Industries,Ltd.

It can be seen from Table 5 that from the comparisons of Example 1-14and Comparative Examples 1-11 to -13, the thermosetting resincomposition containing a fine cellulose fiber composite of the presentinvention product has a high mechanical strength, a relatively hightransparency, and excellent dimensional stability and heat resistance.In addition, it can be seen that from the comparison of Examples 1-14 to-15, when the content of the fine cellulose fiber composite isincreased, the composite has a high mechanical strength and excellentdimensional stability and heat resistance, even though the transparencyis slightly lowered.

Example 1-16 Thermoplastic Resin 2

A fine cellulose fiber composite used in Example 1-4 was subjected to asolvent replacement with methyl methacrylate (MMA), and a solid contentconcentration was adjusted to 1.5% by mass. The amount 5.05 g of thisdispersion of the fine cellulose fiber composite was subjected to afinely pulverizing treatment using a high-pressure homogenizer underconditions of at 60 MPa in one pass, and then at 100 MPa in one pass. Toa solution obtained was added 0.005 g of2,2′-azobis(2,4-dimethylvaleronitrile) V-65B, manufactured by Wako PureChemical Industries, Ltd. as a polymerization initiator, and the mixturewas stirred with a planetary centrifugal agitator Awatori Rentaromanufactured by THINKY CORPORATION for 7 minutes. The polymerizablemixture obtained was injected into a hollow portion of a cell formed bytwo glass plates facing each other and interposing a flexible gasketmade of vinyl chloride, a sealing material for 0.2 mm, the two glassplates having a thickness of 10 mm and being a square of 300 mm eachside. The mixture was subjected to vacuum degassing and nitrogenreplacement, and polymerized at 65° C. for 2 hours. Thereafter, thepolymerized product was dried at 120° C. for 1 hour to provide asheet-like composite material having a thickness of about 0.2 mm.

Example 1-17

The same procedures as in Example 1-16 were carried out except that thesolid content concentration of the dispersion of the fine cellulosefiber composite was changed to 4.3% by mass to provide a compositematerial.

Example 1-18

The same procedures as in Example 1-16 were carried out except that thesolid content concentration of the dispersion of the fine cellulosefiber composite was changed to 16.5% by mass to provide a compositematerial.

Comparative Example 1-14

The same procedures as in Example 1-16 were carried out except that 5.0g of methyl methacrylate was used in place of 5.05 g of the dispersionof the fine cellulose fiber composite to provide a composite material.

Comparative Example 1-15

The same procedures as in Example 1-16 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite used in Comparative Example 1-1 to provide a compositematerial.

Comparative Example 1-16

The same procedures as in Example 1-16 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite used in Comparative Example 1-2, and that a solid contentconcentration was changed to 1.1% by mass to provide a compositematerial.

The properties of the molded article obtained were evaluated inaccordance with the methods of the above Test Examples 5 to 7. Here, inTest Example 6, the numerical values at 100° C. and 25° C. were used. Itis shown that the higher the storage modulus at 25° C., the moreexcellent the mechanical strength. The results are shown in Table 6. InTable 6 the conversion amount of the fine cellulose fibers was obtainedby the above formula.

TABLE 6 Examples Comparative Examples 1-16 1-17 1-18 1-14 1-15 1-16Amine Kinds Amine with Amine with Amine with — PEG n-Propylamine EO/POEO/PO EO/PO Amine Copolymer Copolymer Copolymer Production Example No.of 4 4 4 — — — Amine with EO/PO Copolymer Amount of MMA, parts by mass100 100 100 100 100 100 Amount of Fine Cellulose Fiber Composite, 1.524.49 19.76 0 1.52 1.11 parts by mass Amount of Fine Cellulose Fibers,0.87 2.55 11.23 0 0.87 1.06 parts by mass, Conversion Amount Content ofPMMA Resin 98.5 95.7 83.5 100 98.5 98.9 in Resin Composition, % by massContent of Fine Cellulose Fiber Composite 1.5 4.3 16.5 0 1.5 1.1 inResin Composition, % by mass Property Haze, % 0.3 0.3 0.3 0.3 0.6 1.3Coefficient of Linear Thermal 110 79 34 150 150 140 Expansion, ppm/KStorage Modulus at 25° C., ×10⁹ Pa 2.6 2.8 3.2 2.4 1.8 2.2 StorageModulus at 100° C., ×10⁷ Pa 2.6 3.1 3.9 1.5 1.7 1.6 * PEG Amine: averagemolecular weight 2,000, SUNBRIGHT, MEPA-20H, manufactured by NOFCorporation n-Propylamine: C3 amine, manufactured by Wako Pure ChemicalIndustries, Ltd.

It can be seen from Table 6 that from the comparisons of Example 1-16and Comparative Examples 1-14 to -16, the thermoplastic resincomposition containing the fine cellulose fiber composite of the presentinvention product has a high mechanical strength, a high transparency,excellent dimensional stability, and also excellent heat resistance. Inaddition, it can be seen from the comparisons of Examples 1-16 to -18that even when the content of the fine cellulose fiber composite isincreased, the transparency remains high without being lowered, themechanical strength is high, the dimensional stability is excellent, andthe heat resistance is also excellent.

Example 1-19 Thermosetting Resin 2

A fine cellulose fiber composite used in Example 1-4 was subjected to asolvent replacement with toluene, and a solid content concentration wasadjusted to 1.1% by mass. The amount 3.4 g of this dispersion of thefine cellulose composite, 2.0 g of a styrene-butadiene copolymer SBRNipol NS210, manufactured by Nippon Zeon Co., Ltd, 0.03 g of avulcanizing agent sulfur, 0.01 g of a vulcanization accelerator TBBS,0.06 g of a vulcanization aid zinc oxide, and 43 g of toluene were addedtogether, and stirred at room temperature, 25° C., for 2 hours. Afterhaving confirmed of the dissolution, the solution obtained was subjectedto a treatment at 150 MPa in two passes with a high-pressurehomogenizer. The dispersion obtained was poured to a glass petri dish,and toluene was removed for two days. Thereafter, the residue was driedwith a vacuum dryer for 12 hours, and subjected to vulcanization at 150°C. for 1 hour, to provide a sheet-like composite material having athickness of about 0.2 mm.

Example 1-20

The same procedures as in Example 1-19 were carried out except that thedispersion of the fine cellulose fiber composite was changed from 3.4 gto 17.0 g to provide a composite material.

Example 1-21

The same procedures as in Example 1-19 were carried out except that thedispersion of the fine cellulose fiber composite was changed from 3.4 gto 34.0 g to provide a composite material.

Comparative Example 1-17

The same procedures as in Example 1-19 were carried out except that thedispersion of the fine cellulose fiber composite was changed from 3.4 gto 0 g to provide a composite material.

Comparative Example 1-18

The same procedures as in Example 1-19 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite used in Comparative Example 1-1 to provide a compositematerial.

Comparative Example 1-19

The same procedures as in Example 1-19 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite used in Comparative Example 1-2, and that the amount of thedispersion used was changed from 3.4 g to 2.1 g to provide a compositematerial.

Comparative Example 1-20

The same procedures as in Example 1-19 were carried out except that 0.02g of carbon black was added in place of adding 3.4 g of the dispersionof the fine cellulose fiber composite to provide a composite material.

Comparative Example 1-21

The same procedures as in Example 1-19 were carried out except that 0.1g of carbon black was added in place of adding 3.4 g of the dispersionof the fine cellulose fiber composite to provide a composite material.

Comparative Example 1-22

The same procedures as in Example 1-19 were carried out except that 0.2g of carbon black was added in place of adding 3.4 g of the dispersionof the fine cellulose fiber composite to provide a composite material.

Comparative Example 1-23

The same procedures as in Example 1-19 were carried out except that 1.0g of carbon black was added in place of adding 3.4 g of the dispersionof the fine cellulose fiber composite to provide a composite material.

The properties of the molded article obtained were evaluated inaccordance with the methods of the above Test Examples 6 and 7. Here, inTest Example 7, the numerical values at 100° C. and 25° C. were used.The results are shown in Tables 7 and 8. In Table 7 and 8 the conversionamount of the fine cellulose fibers was obtained by the above formula.

TABLE 7 Examples 1-19 1-20 1-21 Amine Kinds Amine with Amine with Aminewith EO/PO EO/PO EO/PO Copolymer Copolymer Copolymer Production Example4 4 4 No. of Amine with EO/PO Copolymer Amount of SBR Resin, 100 100 100parts by mass Amount of Fine Cellulose 1.87 9.35 18.70 Fiber Composite,parts by mass Amount of Fine Cellulose 1.06 5.31 10.63 Fibers, parts bymass, Conversion Amount Content of SBR Resin 98.2 91.4 84.2 in ResinComposition, % by mass Content of Fine Cellulose 1.8 8.6 15.8 FiberComposite in Resin Composition, % by mass Prop- Coefficient of 114 47 10erties Linear Thermal Expansion, ppm/K Storage Modulus at 3.2 13.3 36.725° C., ×10⁶ Pa Storage Modulus at 2.0 10.9 32.5 100° C., ×10⁶ Pa

TABLE 8 Comparative Examples 1-17 1-18 1-19 1-20 1-21 1-22 1-23 Filler —PEG n-Propylamine Carbon Carbon Carbon Carbon Amine Black Black BlackBlack Amount of SBR Resin, parts by mass 100 100 100 100 100 100 100Amount of Filler, parts by mass 0 1.87 1.16 1 5 10 50 Amount of FineCellulose Fibers, 0 1.06 1.10 0 0 0 0 parts by mass, Conversion AmountContent of SBR Resin 100 98.2 98.9 99.0 95.2 90.9 66.7 in ResinComposition, % by mass Content of Filler in Resin Composition. 0 1.8 1.11.0 4.8 9.1 33.3 % by mass Properties Coefficient of Linear 179 148 146178 166 155 138 Thermal Expansion, ppm/K Storage Modulus at 25° C.,×10⁶Pa 1.3 0.7 1.4 1.6 5.5 14.2 16.1 Storage Modulus at 100° C., ×10⁶Pa0.9 0.4 0.8 1.2 2.9 6.1 7.5 * PEG Amine: average molecular weight:2,000, SUNBRIGHT, MEPA-20H, manufactured by NOF Corporationn-Propylamineamine: C3 amine, manufactured by Wako Pure ChemicalIndustries, Ltd.

From Tables 7 and 8, it can be seen from the comparisons of Example 1-21and Comparative Examples 1-17 to -23 that the thermosetting resincomposition containing the fine cellulose fiber composite of the presentinvention product has excellent dimensional stability, a high mechanicalstrength, and also excellent heat resistance. In addition, it can beseen from the comparisons of Example 1-19 to -21 that if the content ofthe fine cellulose fiber composite is increased, the dimensionalstability is even more excellent, the mechanical strength is high, andthe heat resistance is excellent.

Production Example 2-1 Of Fine Cellulose Fiber Composite—Example 2-1

<Modification with Second Amine>

A beaker equipped with a magnetic stirrer and a stirring bar was chargedwith 157 g of the dispersion of carboxy-group containing fine cellulosefibers obtained in Preparation Example 2 of Fine Cellulose Fibers ofwhich solid content concentration was 1.91% by mass. Subsequently, thebeaker was charged with 0.58 g of aniline (phenylamine), correspondingto 1.5 mol based on one mol of carboxy groups contained in the carboxygroup-containing fine cellulose fibers, 0.58 g of N-methylmorpholine(NMM), and 3.39 g of a condensing agent DMT-MM, and the contents weredissolved in 566 g of DMF. The liquid reaction mixture was allowed toreact at room temperature, 25° C., for 14 hours. After the terminationof reaction, the reaction product was filtered, washed with ethanol, andthe washed mixture was subjected to removal of a DMT-MM salt, washingand solvent replacement, to provide a fine cellulose fiber composite inwhich the fine cellulose fibers were was bound with a phenyl group viaan amide bond.

Here, the binding amount of the modifying group with the second amine,i.e. the binding amount of the second amine, was measured. Specifically,a dried fine cellulose fiber composite was subjected to a determinationin accordance with an ATR method using an infrared absorptionspectrophotometer (IR) Nicolet 6700 manufactured by Thermo FisherScientific K.K., and the binding amount of the modifying group with asecond amine was calculated by the following formula:

Binding Amount of Second Amine (mmol/g)=1.4×[(Peak Intensity of FineCellulose Fibers (Preparation Example 2) at 1720 cm⁻¹−Peak Intensity ofFine Cellulose Fiber Composite (After Modification with Second Amine) at1720 cm⁻¹)÷Peak Intensity of Fine Cellulose Fibers (Fine Cellulose FiberComposite (Preparation Example 2) at 1720 cm¹]

Peak Intensity at 1720 cm⁻¹: Peak intensity ascribed to the carbonylgroup of carboxylic acid

Also, the modification ratio with a second amine was calculated by thefollowing formula:

Modification Ratio (%)={Binding Amount of Second Amine (mmol/g)/CarboxyGroup Content in the Fine Cellulose Fibers Before Introduction(mmol/g)}×100

<Modification with First Amine>

The amount 0.11 g of an amine with EOPO copolymer prepared in ProductionExample 4, i.e. 0.07 mol based on one mol of carboxy groups contained inthe carboxy group-containing fine cellulose fibers, 0/49 g of NMM, and2.83 g of DMT-MM were added to 50 g of the dispersion of the finecellulose fiber composite obtained of which solid content concentrationwas 5.0% by mass, and the mixture was dissolved with 425 g of DMF. Theliquid reaction mixture was allowed to react at room temperature, 25°C., for 14 hours. After the termination of the reaction, the reactionproduct was filtered, washed with ethanol, and the DMT-MM salt wasremoved and washed, to provide a fine cellulose fiber composite in whichthe fine cellulose fibers were bound with a phenyl group via an amidebond, and also bound with an EO/PO copolymer moiety via an amide bond.

Here, the binding amount of the amine having an EO/PO copolymer and amodification ratio thereof were obtained as follows. Specifically, thecomposite was subjected to an IR determination in the same manner asabove, and the binding amount of modifying group with a first amine wascalculated as follows:

Binding Amount of First Amine (mmol/g)=1.4×[(Peak Intensity of FineCellulose Fiber Composite (After Modification with Second Amine) at 1720cm⁻¹−Peak Intensity of Fine Cellulose Fiber Composite (AfterModification with First Amine) at 1720 cm⁻¹)÷Peak Intensity of FineCellulose Fiber Composite (After Modification with Second Amine) at 1720cm⁻¹]

Peak Intensity at 1720 cm⁻¹: Peak intensity ascribed to the carbonylgroup of carboxylic acid

Modification Ratio (%)={Binding Amount of First Amine (mmol/g)/CarboxyGroup Content in the Fine Cellulose Fibers Before Introduction(mmol/g)}×100

Production Example 2-2 Of Fine Cellulose Fiber Composite—Example 2-2

The same procedures as in Production Example 2-1 were carried out exceptthat the amount of the amine with an EOPO copolymer used was changed to0.23 g, that NMM was changed to 0.015 g, and that DMT-MM was changed to0.085 g, to provide a fine cellulose fiber composite. Here, the bindingamount of an amine and the modification ratio were calculated in thesame manner as above.

Production Example 2-3 Of Fine Cellulose Fiber Composite—Example 2-3

The same procedures as in Production Example 2-1 were carried out exceptthat the amount of the amine with an EOPO copolymer used was changed to0.45 g, that NMM was changed to 0.029 g, and that DMT-MM was changed to0.170 g, to provide a fine cellulose fiber composite. Here, the bindingamount of an amine and the modification ratio were calculated in thesame manner as above.

Production Example 2-4 Of Fine Cellulose Fiber Composite—Example 2-4

The same procedures as in Production Example 2-1 were carried out exceptthat the amount of the amine with an EOPO copolymer used was changed to0.135 g, that NMM was changed to 0.088 g, and that DMT-MM was changed to0.509 g, to provide a fine cellulose fiber composite. Here, the bindingamount of an amine and the modification ratio were calculated in thesame manner as above.

Production Example 2-5 Of Fine Cellulose Fiber Composite—Example 2-5

The same procedures as in Production Example 2-3 were carried out exceptthat the amount of the aniline used was changed to 0.29 g to provide afine cellulose fiber composite. Here, the binding amount of an amine andthe modification ratio were calculated in the same manner as above.

Production Example 2-6 Of Fine Cellulose Fiber Composite—Example 2-6

The same procedures as in Production Example 2-3 were carried out exceptthat the amount of the aniline used was changed to 0.20 g to provide afine cellulose fiber composite. Here, the binding amount of an amine andthe modification ratio were calculated in the same manner as above.

Production Example 2-7 Of Fine Cellulose Fiber Composite—Example 2-7

<Modification with Second Amine>

A beaker equipped with a magnetic stirrer and a stirring bar was chargedwith 157 g of the dispersion of carboxy-group containing fine cellulosefibers obtained in Preparation Example 2 of Fine Cellulose Fibers ofwhich solid content concentration was 1.91% by mass. Subsequently, thebeaker was charged with 3.99 g of a 25% aqueous tetrabutylammoniumhydroxide solution, and the contents were dissolved with 300 g ofethanol. The liquid reaction mixture was allowed to react at roomtemperature of 25° C. for 6 hours. After the termination of reaction,the reaction product was filtered, washed with ethanol, and subjected tosolvent replacement, to provide a fine cellulose fiber composite inwhich the fine cellulose fibers were bound with a second amine group viaan ionic bond.

<Modification with First Amine>

The amount 0.011 g of an amine with EOPO copolymer prepared inProduction Example 4, 0.49 g of NMM, and 2.83 g of DMT-MM were added to50 g of the dispersion of the fine cellulose fiber composite obtained ofwhich solid content concentration was 5.0% by mass, and the mixture wasdissolved with 425 g of DMF. The liquid reaction mixture was allowed toreact at room temperature, 25° C., for 14 hours. After the terminationof the reaction, the reaction product was filtered, and washed withethanol, and the DMT-MM salt was removed and washed, to provide a finecellulose fiber composite in which the fine cellulose fibers were boundwith a second amine group via an ionic bond, and also bound with anEO/PO copolymer moiety via an amide bond.

Here, the binding amount of the amine and a modification ratio thereofwere calculated in the same manner as above.

Production Example 2-8 Of Fine Cellulose Fiber Composite—Example 2-8

The same procedures as in Production Example 2-7 were carried out exceptthat the amount of a 25% aqueous tetrabutylammonium hydroxide solutionwas changed to 1.35 g to provide a fine cellulose fiber composite. Here,the binding amount of an amine and the modification ratio werecalculated in the same manner as above.

Preparation Examples 2-1 to -8 Of Dispersion of Fine Cellulose FiberComposite Dispersion—Examples 2-1 to -8

Fine cellulose fibers in the fine cellulose fiber composite of the kindsas listed in Table 9 in an amount corresponding to 0.04 g according tothe following formula, and 40 g of a diester obtained from succinic acidand triethylene glycol monomethyl ether, synthesized in PreparationExample 1 of Plasticizer, as a dispersant were mixed, and stirred with aultrasonic homogenizer US-300E, manufactured by NIHONSEIKI KAISHA, LTD.for 2 minutes. Thus, a plasticizer dispersion of the fine cellulosefiber composite was prepared, of which fine cellulose fiberconcentration was 0.10% by mass.

Amount of Fine Cellulose Fibers (g)=Fine Cellulose Fiber Composite(g)/[1+Molecular Weight of First Amine (g/mol)×Binding Amount of FirstAmine (mmol/g)×0.001+Molecular Weight of Second Amine (g/mol)×BindingAmount of Second Amine (mmol/g)×0.001]

The properties of the dispersion of the fine cellulose fiber compositeobtained were evaluated in accordance with the methods of the above TestExamples 1 to 3. The results are shown in Table 9. Here, the data ofExample 1-4 where only the first amine of the same kind was introducedare attached as a reference.

TABLE 9 Examples 1-4 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 Amine First AmineProduction 4 4 4 4 4 4 4 4 4 (Amine with Example No. EO/PO Binding FormAmide Amide Amide Amide Amide Amide Amide Amide Amide Copolymer) BondBond Bond Bond Bond Bond Bond Bond Bond Second Amine Kinds — Phenyl-Phenyl- Phenyl- Phenyl- Phenyl- Phenyl- Tetrabutyl- Tetrabutyl- amineamine amine amine amine amine ammonium ammonium Hydroxide HydroxideBinding Form — Amide Amide Amide Amide Amide Amide Ionic Bond Ionic BondBond Bond Bond Bond Bond Bond Fine First Amine Binding Amount, 0.38 0.020.04 0.08 0.25 0.08 0.08 0.08 0.08 Cellulose mmol/g Fiber Modification27 1.4 2.9 5.7 17.9 5.7 5.7 5.7 5.7 Composite Ratio, % Second AmineBinding Amount, — 1.12 1.12 1.12 1.12 0.56 0.37 1.12 0.37 mmol/gModification — 80.0 80.0 80.0 80.0 40.0 26.4 80.0 26.4 Ratio, % Total ofBinding Amounts of 0.38 1.14 1.16 1.20 1.37 0.64 0.45 1.20 0.45 FirstAmine and Second Amine, mmol/g Total of Modification Ratio of 27 81.482.9 85.7 97.9 45.7 32.1 85.7 32.1 First Amine and Second Amine, % Ratioof Binding Amounts of First — 0.02 0.04 0.07 0.22 0.14 0.22 0.07 0.22Amine to Second Amine, First Amine/Second Amine Plasticizer Amount ofAggregates, ×10⁴ μm² 0.4 0.8 0.4 0.4 0.6 0.8 0.9 0.5 0.9 DispersionTransmittance, % 99 95 99 99 97 95 94 98 93 Thermal Degradation Temp., °C. 282 207 208 209 212 209 209 209 209

From Table 9, from the results of the comparisons of Examples 2-1 to -4,in a case where a binding amount of the second amine is at a givenlevel, if the modification ratio of the first amine is 3% or so, theaggregates are present in the least amount, and the transmittance is thehighest; and if the modification ratio is higher or lower than theabove, the amount of aggregates is slightly increased and thetransmittance is also slightly lowered. In addition, it can be seen fromthe comparisons of Example 2-3 and Examples 2-5 and 2-6 that in a casewhere the binding amount of the first amine is at a given level, thelarger the binding amount of the second amine, the smaller the amount ofaggregates, and also the higher the transmittance. In addition, it canbe seen from the results of the comparisons of Example 1-4 and Examples2-7 and -8 that similar effects are found even when the second amine isa quaternary alkylammonium.

Example 1-4-2 Thermosetting Resin 1

A fine cellulose fiber composite used in Example 1-4 was subjected tosolvent replacement with methyl ethyl ketone (MEK), the composite ofwhich solid content concentration was adjusted to 2.7%. The amount 16.3g of this dispersion of the fine cellulose fiber composite and 2.5 g ofan epoxy resin jER828 manufactured by Mitsubishi Chemical Corporationwere mixed, and the mixture was subjected to a finely pulverizingtreatment using a high-pressure homogenizer under conditions of at 60MPa in one pass, and then at 100 MPa in one pass. To a solution obtainedwas added 0.4 g of 2-ethyl-4-methylimidazole as a curing agent, and themixture was stirred with a planetary centrifugal agitator AwatoriRentaro manufactured by THINKY CORPORATION for 7 minutes. The varnishobtained was applied in a coating thickness of 1.14 mm using a barcoater, and the applied coating was dried at 80° C. for 90 minutes, toremove the solvents. Thereafter, the coating film was thermally cured at150° C. for 60 minutes, to provide a sheet-like composite materialhaving a thickness of about 0.2 mm.

Example 2-1

The same procedures as in Example 1-4-2 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Example 2-1, that the amount of the dispersion was changedto 10.6 g, and that the film thickness was changed to 0.85 mm to providea composite material.

Example 2-2

The same procedures as in Example 1-4-2 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Example 2-2, that the amount of the dispersion was changedto 11.0 g, and that the film thickness was changed to 0.87 mm to providea composite material.

Example 2-3

The same procedures as in Example 1-4-2 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Example 2-3, that the amount of the dispersion was changedto 11.7 g, and that the film thickness was changed to 0.91 mm to providea composite material.

Example 2-4

The same procedures as in Example 1-4-2 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Example 2-4, that the amount of the dispersion was changedto 14.8 g, and that the film thickness was changed to 1.07 mm to providea composite material.

Example 2-5

The same procedures as in Example 1-4-2 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Example 2-5, that the amount of the dispersion was changedto 11.2 g, and that the film thickness was changed to 0.88 mm to providea composite material.

Example 2-6

The same procedures as in Example 1-4-2 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Example 2-6, that the amount of the dispersion was changedto 11.1 g, and that the film thickness was changed to 0.88 mm to providea composite material.

Example 2-7

The same procedures as in Example 1-4-2 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Example 2-7, that the amount of the dispersion was changedto 13.3 g, and that the film thickness was changed to 0.99 mm to providea composite material.

Example 2-8

The same procedures as in Example 1-4-2 were carried out except that thefine cellulose fiber composite was changed to a fine cellulose fibercomposite of Example 2-8, that the amount of the dispersion was changedto 11.6 g, and that the film thickness was changed to 0.90 mm to providea composite material.

The properties of the molded article obtained were evaluated inaccordance with the methods of the above Test Examples 4 to 7. Theresults are shown in Table 10. In Table 10, the conversion amount of thefine cellulose fibers was obtained by the above formula, and theconversion amounts of the EOPO copolymer moiety and the second aminewere obtained by a calculation from the molecular weight and the bindingamount of the amine.

TABLE 10 Examples 1-4-2 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 Amine FirstAmine, Production No. 4 4 4 4 4 4 4 4 4 Amine with Binding Form AmideAmide Amide Amide Amide Amide Amide Amide Amide EO/PO Copolymer BondBond Bond Bond Bond Bond Bond Bond Bond Second Amine Kinds — Phenyl-Phenyl- Phenyl- Phenyl- Phenyl- Phenyl- Tetrabutyl- Tetrabutyl- amineamine amine amine amine amine ammonium ammonium Hydroxide HydroxideBinding Form — Amide Amide Amide Amide Amide Amide Ionic Bond Ionic BondBond Bond Bond Bond Bond Bond Amount of Epoxy Resin, parts by mass 100100 100 100 100 100 100 100 100 Amount of Fine Cellulose FiberComposite, 17.6 11.4 11.8 12.6 16.0 12.1 12.0 14.3 12.5 parts by massFine Amount of Fine Cellulose Fibers, 10.0 10.0 10.0 10.0 10.0 10.0 10.010.0 10.0 Cellulose parts by mass, Conversion Amount Fiber EOPOCopolymer Moiety, parts by 7.6 0.4 0.8 1.6 5.0 1.6 1.6 1.6 1.6 Compositemass, Conversion Amount Second Amine, parts by mass, 0 1.0 1.0 1.0 1.00.5 0.4 2.7 0.9 Conversion Amount Content of Epoxy Resin in Resin 85.089.7 89.4 88.8 86.2 89.2 89.3 87.4 88.9 Composition, % by mass Contentof Fine Cellulose Fiber Composite 15.0 10.3 10.6 11.2 13.8 10.8 10.712.6 11.1 in Resin Composition, % by mass Property Tensile Modulus, GPa3.3 4.5 4.8 4.6 3.9 3.8 3.6 4.3 4.1 Haze, % 9.0 2.8 2.7 2.8 2.9 2.9 2.92.8 2.9 Coefficient of Linear Thermal 30 12 3 11 23 24 28 18 22Expansion, ppm/K Storage Modulus at 100° C., ×10⁷ Pa 340 470 494 475 400388 369 448 413

It can be seen from Table 10 that from the comparisons of Example 1-4-2and Examples 2-1 to -8, the thermosetting resin composition containing afine cellulose fiber composite in which a first amine and a second amineare used in combination has a high mechanical strength, a hightransparency, excellent dimensional stability, and also excellent heatresistance. In addition, it can be seen that from the comparisons ofExamples 2-1 to -4, in a case where the number of parts by mass of thesecond amine is at a given level, when the number of parts by mass ofthe first amine is 1 part or so, based on 100 parts by mass of theresin, the mechanical strength is the highest, the transparency is high,the dimensional stability is excellent, and the heat resistance is alsoexcellent. In addition, it can be seen from the comparisons of Examples2-3, -5, and -6 that in a case where the number of parts by mass of thefirst amine is at a given level, with the increase in the number ofparts by mass of the second amine, the mechanical strength, thetransparency, the dimensional stability, and the heat resistance areimproved.

INDUSTRIAL APPLICABILITY

The fine cellulose fiber composite of the present invention has highdispersibility in the resin and can exhibit an effect of increasingstrength, so that the fine cellulose fiber composite is suitably used asvarious fillers, and the like. Also, the resin composition of thepresent invention containing a dispersion of the fine cellulose fibercomposite can be suitably used in various industrial applications suchas daily sundries, household electric appliance parts, wrappingmaterials for household electric appliance parts, and automobile parts.

1. A fine cellulose fiber composite comprising fine cellulose fibers anda polymer having an ethylene oxide/propylene oxide (EO/PO) copolymermoiety or a propylene oxide (PO) polymer moiety, the fine cellulosefibers being connected with the polymer via an amide bond.
 2. Thecomposite according to claim 1, wherein the molecular weight of theEO/PO copolymer moiety or the PO polymer moiety is from 500 to 10,000.3. The composite according to claim 1, wherein the average fiber size ofthe fine cellulose fibers is from 0.1 to 20 nm.
 4. The compositeaccording to claim 1, wherein the carboxy group content of the finecellulose fibers is from 0.4 to 3 mmol/g or less.
 5. The compositeaccording to claim 1, wherein the molecular weight of the EO/POcopolymer moiety or the PO polymer moiety is from 1,000 to 5,000.
 6. Thecomposite according to claim 1, wherein the PO content ratio in theEO/PO copolymer moiety is 1% by mol or more and less than 100% by mol.7. The composite according to claim 1, wherein the PO content ratio inthe EO/PO copolymer moiety is 8% by mol or more and 51% by mol or less.8. The composite according to claim 1, wherein the binding amount of theEO/PO copolymer moiety or the PO polymer moiety in the fine cellulosefiber composite is from 0.01 to 3 mmol/g.
 9. The composite according toclaim 1, wherein the binding amount of the amide group having an EO/POcopolymer moiety or a PO polymer moiety in the fine cellulose fibercomposite is from 0.01 to 3 mmol/g.
 10. The composite according to claim1, wherein the amine having an EO/PO copolymer moiety or a PO polymermoiety comprises a compound represented by the following formula (i):

wherein R₁ is a hydrogen atom, a linear or branched alkyl group havingfrom 1 to 6 carbon atoms, a —CH₂CH(CH₃)NH₂ group, or a group representedby the following formula (ii); EO and PO are present in a random orblock form; a is a number of from 11 to 70 showing an average number ofmoles of EO added; and b is a number of from 1 to 50 showing an averagenumber of moles of PO added, wherein the formula (ii) is:

wherein n is 0 or 1; R₂ is a phenyl group, a hydrogen atom, or a linearor branched alkyl group having from 1 to 3 carbon atoms; EO and PO arepresent in a random or block form; c and e show an average number ofmoles of EO added, which is independently a number of from 0 to 50; andd and f show an average number of moles of PO added, which isindependently a number of from 1 to
 50. 11. The composite according toclaim 1, wherein the average fiber size of the fine cellulose fibercomposite is from 1 to 100 nm.
 12. The composite according to claim 1,wherein the fine cellulose fibers are bound with the EO/PO copolymermoiety or the PO polymer moiety via an amide bond.
 13. A method forproducing a cellulose fiber composite as defined in claim 1, comprisingthe following step (A) and step (B): step (A): oxidizing naturalcellulose fibers in the presence of an N-oxyl compound, to providecarboxy group-containing cellulose fibers; and step (B): subjecting thecarboxy group-containing cellulose fibers obtained in the step (A) andan amine having an EO/PO copolymer moiety and/or a PO polymer moiety toan amide-formation reaction.
 14. The composite according to claim 1,wherein one or two bindings selected from the group consisting of thefollowing (1) and (2) may be further introduced to the fine cellulosefibers: (1) the binding via an ionic bond of a quaternary alkylammoniumcation having a total number of carbon atoms of from 4 to 40; and (2)the binding via an amide bond of an aromatic hydrocarbon group having atotal number of carbon atoms of from 6 to
 20. 15. The compositeaccording to claim 14, wherein the binding amount of the quaternaryalkylammonium compound and/or the amine having an aromatic hydrocarbongroup in the fine cellulose fiber composite is from 0.2 to 1.5 mmol/g.16. The composite according to claim 14, wherein a molar ratio of thebinding amount of the amine having an EO/PO copolymer moiety or a POpolymer moiety to the binding amount of the quaternary alkylammoniumcompound and/or the amine having an aromatic hydrocarbon group (theamine having an EO/PO copolymer moiety or a PO polymer moiety/(thequaternary alkylammonium compound and/or the amine having an aromatichydrocarbon group)) in the fine cellulose fiber composite is from 0.01to 0.4.
 17. A fine cellulose fiber composite dispersion comprising afine cellulose fiber composite as defined in claim 1 and a plasticizer.18. A resin composition comprising a thermoplastic resin or a curableresin and a fine cellulose fiber composite as defined in claim
 1. 19.The resin composition according to claim 18, wherein the thermoplasticresin comprises a polyester-based resin or a (meth)acrylic resin. 20.The resin composition according to claim 18, wherein the curable resincomprises one or more members selected from the group consisting ofurethane (meth)acrylate, epoxy resins, and elastomeric resins. 21-28.(canceled)